“What are the chances of us becoming a couple? Zero. It’s impossible.”

Jung Yihan lost her family in an accident when she was a child and grew up under the care of Han Chioh’s family.
As they grow older, she begins living with the “older brother” next door, with whom she has only built up awkwardness...

How will their relationship change, as they keep intruding on the feelings they’ve both kept carefully hidden?