Dr. Tin, fails to save the life of young man injured in a car accident. After falling asleep, he wakes up a few hours in the past, forced to relive the death in a cycle over and over again.
After repeatedly failing to save Tol's life, Tin attempts to intervene earlier in the day to help Tol avoid the accident altogether. However, his attempts have consequences as changing the past effects the future.
Tin takes a new strategy of getting Tol to the hospital in hopes of getting him to take test for his heart. Afterwards, he rushes to Rit's house to stop him from drinking the insecticide.
Tin waits for Tol outside the party, and Tol remarkably survives the night due to Tin's actions. However, the next day tragedy strikes on multiple ends disrupting the timeline in ways Tin hasn't yet seen.
With the finding of the root cause of Tol's death, Tin realizes he will need to go back further in time to save Tin, as well as Rit and Fang. However, the further Tin goes into the past, the less he can remember what has already happened.
After spending the day with Tin, Tol awakes from a nightmare where he saw his own death repeatedly. The next day at school, Tol remembers Tin's advice about doing the right thing to make amends with Rit.
After locating Jinta, Tol is offered one chance to change the past and correct their future. However, Jinta's opportunity does not come easily, and Tin cannot remember his relationship with Tol at all.
With Tin's memories gone, Tol struggles to get close to him and earn his trust. Meanwhile, Prof. Sak uses Tin's pain from his sister's death to try and lure him into his scheme.
