Sungmin is Yunho's runaway bride who went missing for weeks. Worried, Yunho went to look for him only to find out he's in Busan searching for his high school  ex-boyfriend- who is now a happy married man. Yunho convinced him to go home with him- to their little apartment in US.. but he chose to stay.

He chose to stay, for this stranger he met..

A committed stranger he met while exploring both their Past.

Relationship.

And each other.