3.5th Period
In Shin-ha High School, there's a secret hidden between the 3rd and 4th periods. It's the existence of a 3.5th period where time flows ten times slower, turning 10 minutes into 100. Baek Ah-jin accidentally enters the 3.5th period and meets Kang Da-won, a male student trapped there. To help Da-won escape from the 3.5th period, Ah-jin unravels the mysteries hidden there. However, there are those who hinder their efforts and strive to conceal the 3.5th period. What secrets are hidden in Shin-ha High School's 3.5th period? Will Da-won successfully escape and reunite with Ah-jin?