Hae Jun discovers a time machine while Yoon Young struggles with her busy job until tragedy strikes.

Yoon Young thinks that it could be a good thing that she somehow ended up in 1987 and met Soon Ae.

Yoon Young joins Soon Ae's class as planned, but a sudden twist drastically disrupts everything.

Hae Jun's expectations are challenged as events unfold, until a student teacher enters the scene.

Yoon Young's choice to withhold the specifics of her reasons for staying might have been an error.

Despite Hae Jun's confidence in his thorough preparations, it turns out they are insufficient.