The hotshot professor at Korea’s number one university is even on his way to the presidency. Geun Woo plays the perfect husband in front of his family but is actually being unfaithful to his wife Hye Ryul. Meanwhile, Hye Ryul goes up against Jusung although it is run by her in-laws. This case goes viral and grabbed the whole nation’s attention.

The Christmas Fund that many people talk about is suspected as the cause of a person’s death. Certain that it is a murder case, Gu Won digs deeper despite the danger. Hye Ryul gains enough power to compete with her husband for the presidency. Nobody is able to figure out what the competent couple has in mind.

Gwang Jeon finds out about Geun Woo’s affair, but does not use it against him yet. However, she is not the only one who knows about it. Meanwhile, crucial information regarding Hye Ryul’s investigation gets leaked to the press. Although it causes some difficulties, it does not stop her from doing what she thinks is right.

Nan Hee asks Hye Ryul to buy her a drink after she helps her with the computer. As Geun Woo also tags along, the air becomes tense. Meanwhile, Hye Ryul decides to help the police with their investigation on the Christmas Fund. Just before their great arrest, something goes sideways and their only chance disappears.

After watching Ji Joon Ki’s interrogation, Hye Ryul asks Geun Woo out to dinner. At the couple’s favourite restaurant, Hye Ryul tries to comfort her husband by showing how much she appreciates him putting up with her mother. Just then, Kang Baek shows up with his friends and suggests that they join Hye Ryul and Geun Woo. Geun Woo’s face stiffens.

To sabotage Nan Hee’s plan, Hye Ryul asks Kang Baek to bring Ji Yi home for dinner to discuss their marriage. The whole family gathers and prepares a feast to welcome their future family member, Ji Yi, only to be surprised by who turns up at the door. When Ji Yi finds out about the dinner, she asks her dad to stop the investigation on Jusung.

News reports on Chairman Ji’s letter and his claims give Hye Ryul and everyone involved in this case a headache. But what torments Hye Ryul the most is what Nan Hee tries to do with her son. When Hye Ryul gets a text from Kang Baek that he might not come home, she starts to fret frantically. Meanwhile, Geun Woo meets with Nan Hee to try and stop her from using Kang Baek for her revenge.

At the mock trial competition, the students argue over a case that’s made up based on the actual case from 20 years ago. During the trial, Nan Hee becomes overly zealous, which piques Gun Do’s interest. Meanwhile, Hye Ryul and Geun Woo’s kiss in the car made the headlines, successfully diverting the public’s attention from the investigation.

Gun Do invites Nan Hee over to his office to offer her compensation in order to silence her. But it is not enough. Nan Hee threatens Gun Do that something else will be on the news if Ham & Lee doesn’t apologize publicly for what they did to her father. The next day, a woman’s body is found floating on the lake at Minguk University, which shocks many. Eun Mi assumes the informant she was supposed to meet the night before is the victim and wants to help with the investigation.

The body is confirmed to be Nan Hee, but it is strange that those who should be the most shocked are calm about this. The detectives try to find clues, but it seems that the culprit has been pretty thorough. Meanwhile, those who were close to or around Nan Hee when she was alive started to become suspicious of one another. While Hye Ryul is extremely anxious about Kang Baek, Geun Woo receives an anonymous letter.

Hye Ryul demands that Geun Woo tell her what he knows about Nan Hee’s plan. While Geun Woo feigns ignorance, Hye Ryul also finds out that her mother knew about Geun Woo’s affair with Nan Hee all along. Meanwhile, Ji Yi declares that she’ll marry Kang Baek even though the public suspect Kang Baek as the killer.

Gwang Jeon tells Geun Woo to make it look like Gu Ryeong is the killer. Knowing she’d go to any lengths to protect her grandson, Geun Woo can’t dare to tell her that he’s being blackmailed. Meanwhile, Hye Ryul pushes forward with her investigation of Jusung rather harshly, causing Moo Ryul to come and provoke Hye Ryul.

Kang Baek has been feeling guilty and suppressed about his true love because of his family and their belief. But his friends all knew about his secret love and wanted to protect him. Meanwhile, thanks to Geun Woo’s help, Gu Ryeong comes off the suspect list. When Hye Ryul hears of this, she gets furious and heads to Geun Woo’s office.

Although Kang Baek was with someone who could confirm his alibi on the night of the incident, he chooses to remain silent and be questioned by the police. Unaware of this, the whole family becomes anxious and worried about Kang Baek. Before taking Kang Baek to the police, Geun Woo takes him to his mother’s grave, where the two have an honest talk.

The whole family is crushed by Kang Baek’s death except for Min Heon. Ae Hun, who cannot stand to spend another second with the monster, musters up her courage and comes to a decision. Meanwhile, Hye Ryul visits the lake where Nan Hee’s body was found, thinking about the conversation they had before she died.

After watching what was in Nan Hee’s flash drive, Hye Ryul makes up her mind and resumes the investigation on Jusung. Nan Hee’s murder case also gets re-investigated, and it seems the true culprit is indicted. But what really happened on the day Nan Hee died?