We kiss in three seconds.

Sachi is a quiet high school student who has a secret crush on her childhood friend, Yuuto. She has never been able to confess her feelings, and their relationship remains stuck in the comfortable but stagnant zone of friendship.

One day, Yuuto suddenly kisses her, counting down from three before doing so. This unexpected act throws Sachi into confusion, as she struggles to understand his true intentions. Is it a game, a joke, or something more? As they continue this strange ritual, Sachi must navigate her growing feelings and the uncertainty of what Yuuto really wants.