In Yanxue Academy in Kyoto, Su Wan, a princess who disguised herself as a man, and Pei Yan, an illegitimate student, were classmates who supported each other. However, they were publicly humiliated by Pei Yan due to a misunderstanding about "stealing papers". Su Wan activates the "event selection causal system" and can see the causal lines of different choices every time she faces a choice - to protect her dignity, she chooses "fighting back in public", which actually triggers the causal chain that Pei Yan's grandfather was saved by the Su family; to find out the truth, she chooses "visiting the library at night", which also reveals the hidden story of Pei Yan's mother being forced to death by Su's father's old subordinates. In the sadistic tug-of-war between the two, Su Wan uses the system to reverse the dilemma of being framed and isolated again and again, while Pei Yan gradually discovers that his heartbeat for "Mr. Su" is actually his long-standing obsession with Su Wan, who is a daughter. Finally, in the "confession" option prompted by the system, all misunderstandings are revealed and two-way redemption is achieved.
