A group of friends are forced by unknown people to find a masked killer within 100 time loops.
Wushi and his friends board a high-speed tourist train under the sea that was used to experiment on time travel.
The train derails when it approaches the destination. Right at that moment, everything returns to the middle of the trip, again and again. Wushi remembers every loop, and he is forced to experience those pains and fears repeatedly.
Except for Wushi, no one seems to remember previous loops. In the latest loop, Wushi notices a masked stranger on the train attacking innocent students.
It turns out that time travel is fueled by corpses, and more loops require more deaths.
Before a total mental breakdown, Wushi needs to identify the mastermind and the real identity of the masked murderer among 200 passengers.
Wushi: An optimistic fool with a great intuition for truth who gets caught in a never-ending time loop.
Seyue: The only successor of a major business group, and the inventor behind the time machine. She works with Wushi to identify the perpetrator and break through the time loop.
S: This masked stranger appears in the time loop and attacks students on the train.