1x14 - Tomorrow with You

Yong Jin sees So Joon vanishing into thin air while riding the subway. After that, Yong Jin goes to Ma Rin’s house and tells her what he saw. When he leaves, Ma Rin and So Joon talk about how there is no way he’d know how So Joon is a time traveler. Little do they know, Yong Jin is listening to their conversation over the bug he planted when he was at their house.