When Adnan lost his wife eleven years ago, he withdrew from social life and retired to his mansion, giving all his attention to his daughter Nihal and son Bülent. Adnan Bey, who lives in one of the most important mansions of Istanbul with his family heirloom veterans, Behlül, the child of a distant relative, who is half a French nanny and patron of the children, begins to remember the feelings he has forgotten and sprout spring in the middle of winter, after meeting Bihter, the daughter of Firdevs Hanım from the Melih Bey team, one of the well-known families of Istanbul, years later.

Bihter accepts Adnan's marriage proposal. Adnan, whose proposal is accepted by Bihter, is very happy. However, he is uneasy about how to explain the situation to his daughter Nihal. The acceptance of her family, especially her daughter, remains important to her. Bihter's anger towards her mother has turned her relationship with Adnan into a revenge plan. He is waiting for the right time to explain everything. Adnan's dinner invitation for the families to get closer to each other will also be the beginning of some events to be revealed. While Firdevs, who is unaware of everything, dreams about Adnan, Behlül starts to look at Bihter from a different perspective for the first time. A big surprise awaits Firdevs, who plans to improve his financial situation by marrying Adnan.

Adnan and Bihter are alone in the mansion for the first time. Firdevs Hanım takes a big blow when she learns that Adnan Bey, whom she thinks of as a husband candidate for her, wants to marry her daughter Bihter. Although Bihter knew her mother's interest in Adnan Bey, she remained silent and started to watch her mother's defeat with great pleasure. This becomes the last point of the secret war between Ms. Firdevs and Bihter. Firdevs Hanım vows to take her revenge on Bihter sooner or later.

Ms. Firdevs is secretly happy that this marriage will not be easy for Bihter. Bihter brings the marriage date forward even more so as not to justify her mother. Behlül realizes the conflict between Firdevs Hanım and Bihter. Istanbul society is eagerly waiting for this important event, which will be considered the wedding of the year. Both Nihal and Bülent are excited about their father's wedding. For Ms. Firdevs, this wedding will be a show of strength again. But Adnan and Bihter insist on a simple and elegant wedding, away from all kinds of ostentation. However, the wedding of the year turns into the scandal of the year.

While Ms. Firdevs claims that she has been slandered, Bihter is determined to hold her to account for the ruined wedding. Bihter makes everyone feel her presence in the house from the very first day. He wastes no time in making changes to the layout of the house. On the other hand, he looks for ways to get closer to Nihal. Behlül decides to question the authenticity of Hilmi Bey's claim. His visit to Hilmi Bey and Firdevs Hanım's warnings make Behlül nervous. Adnan's plans for Nihat, who is in a difficult situation, increase Behlül's concerns.

Thinking that Behlül is gone because of Bihter, Nihal reacts to Bihter. He is uncomfortable with her having a say in the house so quickly. However, Bihter has slowly started to win Bülent's heart. While things get better for Nihat, who starts working in a good position with Adnan Bey, troubled days begin for Behlül. Adnan Bey and Bihter's long honeymoon program coincides with Nihal's birthday. Behlül will not leave Nihal, who is sad to celebrate separately from her father for the first time.

Nihal's reaction to Behlül's departure from home affects Adnan Bey. Although Bihter is not eager for Behlül to return, Adnan Bey takes a step for Behlül to return home. However, Behlül has other plans that will benefit Adnan Bey. Nihal's fling with Pelin is no longer a secret between her and Behlül. Nihal, who wants her father to hear the truth from her, is waiting for the right moment to talk to Adnan Bey. However, the big surprise that Bihter has prepared for Nihal and Bülent changes the agenda. After this incident, Nihal will see Bihter as a real rival and danger to her.

Nihal, who thinks that she is slowly being removed from all her loved ones, cannot digest Bülent's address to Bihter as "mother". After her father, Behlül and Mademoiselle, Bihter has now taken Bülent away from her. For the first time, Nihal does not hide her feelings for Bihter. Bihter now understands that Nihal will be an important obstacle between her and Adnan. Adnan, who is aware of Firdevs' debts, now has question marks in his mind against Bihter and begins to think that there are other reasons behind Bihter's marriage to him.

Ms. Firdevs was seriously injured as a result of a traffic accident. Bihter, who shouted her hatred for her mother in her last arguments, now has completely different feelings. With this incident, tensions between Bihter and Behlül are put aside, but Nihal is uneasy that Behlül approaches Bihter, even if it is to console her. Realizing this platonic love, Mademoiselle decides to take the necessary precautions. While Ms. Firdevs's situation remains heavy, Bihter opens the door to the past and sees her mother's dark face.

Firdevs Hanım survives the life-threatening situation. While Ms. Firdevs's mansion is being evacuated, Bihter asks her mother to stay with her temporarily after she leaves the hospital. Ms. Firdevs welcomes this decision. Adnan Bey, Mademoiselle, Nihal and Beşir go to Ankara for Bülent's match. When Behlül gets fired up and comes home, it is up to Bihter to heal Behlül. Behlül becomes uneasy about the attraction he feels towards Bihter. Firdevs Hanım, who settled in the mansion, immediately notices the rapprochement between Bihter and Behlül.

Firdevs Hanım, who stayed in Adnan Bey's mansion temporarily after her accident, adopted her room and got used to the house. Bihter, who is at an important decision stage, shares this situation with her mother and sister before her husband Adnan. The walls of this mansion, which has never held any secrets before, are too thin to hide even small secrets.

Hearing what Firdevs said to Bihter about her pregnancy, Adnan becomes suspicious about her marriage. Their falling out falls out when Bihter fires her veterans working in the kitchen of the house. Behlül returns to the past he does not want to remember with bad news. He goes to Mersin with Adnan Bey for a short time. On the return of this forced trip, big storms will break out in the house.

Bihter, who panics when she feels that Adnan is starting to move further away from her, makes a big rebuke to her husband. Although Bihter tries to recover the situation with the tactics she received from Ms. Firdevs, it will not be easy to win the heart of Adnan Bey, who cannot digest what happened. In a panic, Bihter takes refuge in a safe harbor in the dark of night.

Nihal's piano recital changes everyone's agenda at home. Nihal invites the housekeepers to the recital with her whole family. According to Ms. Firdevs, this invitation is an important indicator of the cold war that Nihal started against Bihter. Adnan Bey, on the other hand, fears being misunderstood and asks Nihal to withdraw his invitation. Nihal's step back is a big disappointment for Cemile. With this event, the ranks were clearly determined and cold winds started to blow again in the house.

Nihal has taken a stand against Ms. Firdevs because she overshadowed her success. Firdevs falls out of favor with Adnan Bey because of the events he has caused. Realizing this, Bihter decides to look for a new place for her mother to stay. On the other hand, Bihter finds the love notes Behlül wrote to Peyker among Peyker's personal belongings. These memories of the past will pose a great danger to Bihter's marriage.

Adnan Bey, who thinks that the love note written by Behlül was written to his wife, feels like he has been shot in the back. This misunderstanding, which will leave a mark on Adnan Bey's marriage, will also cause great tension for Behlül and Bihter. Although they object to Adnan, they know deep down that they are not innocent. Peyker's confessions about her passionate love with Behlül in the past bring Bihter's suppressed feelings to the surface. Memories of the past begin to cast a shadow on the relationship between the two brothers

Since Firdevs Hanım is aware of the electricity between Bihter and Behlül, she tries to save Bihter's marriage in her own way and tries to make a wedge between Behlül and Nihal. He encourages Nihal and Behlül against each other. The dangerous games played by Ms. Firdevs will make Bihter face her true feelings. Bihter is determined to prevent Behlül and Nihal from getting closer to each other.

Behlül cannot even admit to himself what he feels for Bihter. He tries to find out Bihter's feelings, but Bihter does not come to the game. Bihter, who feels uneasy about Behlül, asks for a small weekend getaway to get away from him and get closer to Adnan. On Bihter and Adnan's return from their travels, a small celebratory dinner is organized for Peyker's baby at home. Behlül will also attend the celebration, albeit late. The good news that Behlül will give shocks Bihter and Nihal.

Behlül and Elif's decision to marry comes as a surprise to the whole family. While Bihter hides her true feelings about the news on the agenda, there is a great rush at home with the reaction of Nihal, who cannot handle this situation. The first stop of the holiday that Adnan Bey and Bihter take with their children will be Uludağ. Nihal and Bihter are glad to be away from Behlül. The holiday, which starts peacefully, continues with Behlül's surprise. Bihter, who is cornered when she least expects it, takes the first wrong step about Behlül.

When the Ziyagil Family returns from their Paris vacation with Ms. Firdevs, they find Elif settled in the mansion. This situation disturbs Bihter and Nihal very much. Behlül's passion games using Elif enable Bihter to face her passions. On the other hand, Deniz, whom Nihal met in Uludağ, wants to meet Nihal again. Nihal, who secretly likes Behlül's opposition to this situation, takes a step towards Deniz. On the other hand, Nihat's mother, Aynur Hanım, learns the details about the woman she thinks her husband is having an affair with. When Peyker realizes that that woman is Behlül's fiancée Elif, she shares it with Bihter. Bihter makes a plan for the truth to come out.

Suspecting that Elif is having an affair with Hilmi Bey, Bihter plays a game to make sure of this and sees with her own eyes that her suspicions are real. Tamper with the case, Behlül tries to find out Bihter's intentions. However, Behlül, who regrets going after Bihter, looks for different ways to apologize. Bihter, on the other hand, takes refuge in Adnan Bey's love to get away from Behlül. Behlül, who could not get the response he expected from Bihter, does not let go of Bihter and takes the first irreversible step towards the ban.

Firdevs' watchful eyes immediately notice the change in Bihter and Behlül. Firdevs, who goes over the smell he gets, will be the cause of new tensions in the house. Bihter decides with Adnan Bey to get engaged to Behlül and Elif immediately in order to get rid of her contradictory mood as soon as possible and get away from Behlül. Behlül, who tries to get away from Bihter in a silent agreement, cannot hide his feelings on the night of the engagement. After the rings are worn, Mr. Adnan will come face to face with a reality.

Thinking that her mother has started to pose a great danger at home, Bihter decides to take her revenge on Firdevs by using Adnan. Firdevs, who realizes that he has nothing left to lose, decides to tell Adnan what he knows. The tears shed by Nihal on Behlül's engagement night cast doubt on Adnan Bey. Adnan Bey, who questions the real reason for his daughter's sadness, is shocked by what he learns.

Realizing that he will be sent from home, Firdevs decides to use his big trump card and tell everything he knows. Cornered, Bihter submits to Firdevs. Bihter blames Behlül for losing to her mother and the tension between them escalates. Firdevs starts to play new games, this time against Adnan, to ensure his dominance in the house. He will get what he wants with every step he takes.

When Firdevs' wishes begin to push the limits because Bihter submits to her mother, Adnan Bey begins to take some precautions in his own way to prevent the balance in the house from being disturbed. While this situation creates great tension between him and Bihter, Nihal begins to question the tension in the house. Behlül, who cannot get Bihter out of his mind, has feelings he has never experienced before. He even runs away from himself to prevent what he thinks of doing. Bihter will be shaken by Behlül's confession.

On the night Behlül disappears, Elif, who thinks that she is cheating on her with one of her exes, sends her engagement ring back. Behlül is more interested in telling Bihter that they could not even confess to himself while he was drunk, rather than the breaking of the engagement. Bihter, on the other hand, begins to discover a completely different side of Behlül. Bihter, who succumbs to her momentary weakness, realizes that she cannot lie to herself anymore. The fire that burns secretly will soon turn into a big fire.

Realizing that he cannot stay away from Bihter in Adnan's absence, Behlül tries to escape from himself. However, both Behlül and Bihter cannot resist their emotions. Passion fuels love. The sparks of this love begin to splash on the walls of the Ziyagil mansion.

As the boundless attraction between Bihter and Behlül becomes more and more dangerous, Behlül makes a new decision that surprises everyone to get rid of his feelings for Bihter. Every step they take to get away from each other brings Bihter and Behlül closer with longing. The meaningful gift that Behlül will give to Bihter on her birthday ignites a great spark.

Firdevs Hanım, whose gambling club is raided by the police, is taken to the police station. Adnan Bey immediately takes action to prevent this scandal from tarnishing the name of 'Ziyagiller'. Hilmi Bey, who has a big trump card in his hand, manages to use this situation to his advantage to get his ambition from Ziyagiller and Firdevs Hanım. This event, which triggers a great power struggle, changes all the balances and casts a shadow on Peyker and Bihter's relationship. Bihter decides to celebrate her birthday outside as a family to get rid of the effects of what happened. At the end of the night, the pain of forbidden love takes over Behlül and Bihter. Firdevs Hanım, who is very embarrassed by what happened, takes a step into the darkness with the last blow she receives.

Struggling with brand new fears, Behlül and Bihter resist not to surrender to forbidden love. When longing fuels love, Bihter takes a surprise step towards Behlül. In Ziyagil Mansion, while 'forbidden love' is passionately out of control, a smoldering fire shows its face for the first time in another room of the mansion.

Bihter, who finds her husband with Mademoiselle in an unexpected way, sees Mademoiselle as a great danger, even though she cannot admit it. Bihter and Behlül, who stop and regret every step they take, gradually realize that the danger is growing. In this case, as always, "Behlül escapes". This situation made Bihter very angry. Following her suspicions, Mademoiselle begins to piece together the missing pieces of the forbidden story. Backed into a corner, Bihter and Behlül hatch a plan to eliminate the threat.

In the dark of the night, Bihter, who is caught by Adnan while rummaging through the drawers in Mademoiselle's room, is in a very difficult situation. This incident, in which Behlül is also involved, causes a big crisis between Bihter and Adnan. In Adnan's absence, the flames of forbidden love spread to every corner of the house, making it increasingly difficult for the lovers to stay away from each other. The tensions between Bihter and Adnan affect Nihal the most. Behlül, who consoles Nihal on the one hand and listens to his uncle's sadness on the other, is in a state of disarray. Trapped between their consciences and their passions, the two lovers begin to be crushed by the burden of forbidden love.

Bihter and Behlül are tired of being torn between bitter reality and dreams. Bihter, who wants to get rid of the grip of forbidden love, offers Behlül to leave, leaving everyone behind. The lovers of forbidden love, who set out to implement their decision with fears they cannot admit, enter an irreversible path that drags each other into the abyss.

Bihter and Behlül's plans, which take action to leave everyone behind and escape, are turned upside down when Behlül takes a step back at the last minute. Bihter, who leaves behind a letter to Adnan in which she confesses her true feelings, is in a very difficult situation. She needs help to save her marriage and prevent Adnan from reading this letter. This event, which grows with surprising developments, puts Bihter in a corner.

The rumor that Behlül might have had a fatal accident in Azerbaijan brings the Ziyagil family in dismay. Much to everyone's delight Behlül is still alive. After hearing parts of a phone conversation, Nihat suspects that Behlül has an affair and therefore wanted to get back to Istanbul as quickly as possible. His wife Peyker realizes that the woman could be her sister.

Besir witnesses a long-haired woman, whom he mistakes for Nihal, and Behlül kissing on the balcony. Only Deniz realizes that Behlül and Bihter were kissing each other in the middle of the night. Besir openly confronts Behlül with what he saw. Peyker, on the other hand, confronts Bihter with her suspicion. However, she believes that the attraction is one-sided, namely that Behlül alone is interested in her sister.

Mademoiselle, who realizes that Bihter is the shadow that Beşir thinks is Nihal in the dark, is shaken by the reality she faces. This secret, which she cannot share with anyone, begins to become an increasingly heavy burden for Mademoiselle. Nihal's graduation with honors makes Adnan Bey very proud. Everyone witnesses the incredible change of Nihal, who goes to the graduation ball on the same night. The fact that Behlül will accompany Nihal at the ball makes the night even more meaningful for Nihal. On this happy night of Nihal, Bihter will also have a big surprise for Behlül.

Nihal has a hard time hiding her love for Behlül under the influence of the night. Although Bihter does not want to show it, she is jealous of Behlül's accompaniment to Nihal. Bihter, who surrenders to her feelings with the effect of jealousy, calls Behlül and confesses her love. After that, it becomes even more difficult for the two lovers to resist each other. On the day of the exam, Mr. Adnan does not want to leave Nihal alone. Behlül and Bihter, who want to take advantage of this opportunity, make a very special plan to be alone for the first time. However, surprise developments that will affect everyone change all plans. When forbidden love flares up with passion, Bihter and Behlül walk into the fire without fear.