In a post-virus world with Alphas, Betas, and Omegas, Alpha Sheng Shaoyou seeks help from HS Group for his father's treatment. At the hospital, he meets Omega Hua Yong, who works for his competitor.

While seeking investors for drug research at a club, Sheng Shaoyou meets and helps Hua Yong, who needs money for his sister's medical care. Sheng secretly pays the bills, and they grow closer.

The relationship between Hua Yong and Sheng Shaoyou deepens with various acts of service performed by Shaoyou, eventually turning into Hua Yong moving in. Shaoyou realizes that his feelings for Hua Yong go beyond friendship.

Hua Yong reveals he's limited to intimacy with his marking Alpha, upsetting Sheng Shaoyou. Gao Tu struggles with hidden identity and pheromone issues, found by Shen Wenlang. X Holdings' push leads to business peak.

Gao Tu's suppressant abuse worsens his condition. As Sheng Shaoyou and Hua Yong grow closer, Shaoyou's marking proposal is rejected. Hua Yong disappears, and despite Shaoyou's search efforts, remains missing as his true identity emerges.

Hua Yong's true identity as the mastermind behind X Holdings is revealed. The misunderstandings between Shen Wenlang and Gao Tu deepen, and Gao Tu wants to resign. Sheng Shaoyou successfully brings Hua Yong back, and in order to protect him, he decides to go to war with HS Group.

Hua Yong overdoses on pheromones and ends up hospitalized. Shen Wenlang secretly visits him, but the meeting doesn’t go well. After being discharged from the hospital, Sheng Shaoyou takes Hua Yong out for dinner and happens to meet Shen Wenlang, where a conflict breaks out.

Sheng Shaoyou’s condition worsens after losing control of his pheromones and gets hospitalized. X Holdings invites Shaoyou to a private gathering, but the effects of the pheromones cause him to fall into a coma, which causes chaos.

Hua Yong deliberately sows discord to help Sheng Shaoyou obtain the targeted drug. Unexpectedly, Hua Yong loses control during her susceptible period, mistaking Sheng Shaoyou for an Omega, leading to an irreparable misunderstanding. Meanwhile, Gao Tu also loses control, which accidentally allows Shen Wenlang to discover his true Omega identity.

Gao Tu hides his Omega status and isolates himself, making Shen Wenlang suspect infidelity. As Sheng Shaoyou and Hua Yong share a tender moment, an earthquake strikes. Hua Yong's powerful protection makes Shaoyou question his Omega nature.

Sheng Shaoyou finally learns that the mysterious person who made him lose control previously was none other than Hua Yong, who was covered in wounds and trying hard to release soothing pheromones. Meanwhile, interactions between Hua Yong and Shen Wenlang deepens Shaoyou's misunderstanding, and a conspiracy against him quietly unfolds.

Sheng Shaoyou was kidnapped and injected with a deadly toxin. To save him, Hua Yong had no choice but to mark him permanently as Enigma. After the marking, the two become passionate and Shaoyou makes a confession. Meanwhile, Gao Tu makes a decision to resign, triggering misunderstanding and anger from Shen Wenlang.

Gao Tu resigns after learning of his pregnancy, planning to handle it alone. Hua Yong reveals he's Enigma and has loved him for 15 years, leaving Sheng Shaoyou stunned. Hua Yong strives to earn his trust.

The relationship between Sheng Shaoyou and Hua Yong heats up rapidly. However, Shaoyou's younger brother Sheng Shao Qing has ulterior motives which forces Hua Yong to protect his beloved.

Sheng Shaoyou and Hua Yong are both hospitalized. Hua Yong is seriously injured and in a coma, yet he remains by Shaoyou's side. After several blood tests, Shaoyou is shocked to discover he's pregnant. Gao Tu insists on having the baby and cuts off contact with Shen Wenlang, leaving Wenlang extremely anxious and finally confronting his feelings for Gao Tu.

Sheng Shaoyou accepts Hua Yong’s proposal, but their pregnancy is fraught with danger. Three years later, the two of them and their baby led a happy life. Shen Wenlang also reunites with Gao Tu, and their emotional journey finally finds an ending.