In a world wherein people find their soulmates through a simple touch, Kang Seulgi finds a whole new universe within hers – Bae Joohyun. Or, just two clueless souls being soulmates.

When Minjoo's Valentine's day date didn't go well, Chaewon was there to try and save the night.

Minjoo moved to the house next to Chaewon's and since that day their lives were never the same. This is the story of how their fellings changed through time and they grew closer as friends and then lovers, one step at time.

At the night before their high school graduation Chaewon and Minjoo promised one thing: To marry each other if they were still single by the age of thirty. Eleven years went by, but none of them forgot about the promise.

Luda and Jiyeon have known each other for years, both harboring untold feelings. Can one night change it all?