When they first met on a rainy night, Gu Yanci deliberately pulled her into his world in order to investigate old cases of the Su family, on the condition that she could pay for Grandma Su Nian's medical expenses and arrange an internship. After Su Qingyuan found out, she secretly filmed and provoked, which caused Jiang Chen to misunderstand and break up with Su Nian. At the dinner, Gu Yanci strongly declared his sovereignty and crushed Jiang Chen. He even bluntly said that "Mother Su owes him something that needs to be paid back." This revealed the foreshadowing of an old case, and the two fell into the beginning of a sadomasochistic relationship of "exploitation and temptation".
After that, Gu Yanci used the old case to firmly control Su Nian. During a fierce argument, he lost control of his love and possessiveness, and took away Su Nian's innocence despite her resistance. Su Nian was traumatized both physically and mentally, hated and afraid, but was unable to escape due to her grandmother's illness. After learning about it, Jiang Chen appeared frequently and tried to take her away, which only aroused Gu Yanci's suspicion and possessiveness, and the sadomasochism escalated - he forced intimacy while hurting Su Nian with cruel words. Su Qingyuan took the opportunity to frame her, fabricating the illusion that Su Nian and Jiang Chen were reunited, leaking secrets, etc., Which deepened the misunderstanding between the two. Gu Yanci hurt Su Nian in a rage, but fell into regret and self-struggle afterwards.
As the investigation deepens, Gu Yanci discovers that Su's mother is not the real murderer, but may be the victim. The mastermind behind the crime is actually the villains from the Su and Gu families who jointly framed the case. Su Nian also found key clues when sorting out her mother's belongings. In the process of "jointly chasing the murderer", the two gradually let go of their barriers and saw each other's sincerity clearly. Su Qingyuan's conspiracy was exposed and she completely lost everything; Jiang Chen recognized the reality and chose to let go and bless her. The truth of the old case was revealed, Gu Yanci sincerely confessed to Su Nian for the past harm, and the two of them solved all the knots in their hearts. After going through the ordeal of sadomasochism, they finally spoke frankly to each other.
