It's the zombie apocalypse and a loner Momo stumbles upon a bubbly and optimistic Sana while she's looking for shelter one night. Even if Momo doesn't trust people easily, Sana somehow manages to tag along The two might disagree on a lot, but start becoming attached to each other. 

Twice is on a vacation at the beach without managers. Jeongyeon finds Jihyo on the beach at night and the latter confesses her feelings.