Sera is a nerdy yet talkative girl who lives with her parents at her cousin, Do kyungsoo's enormous house. Her worst enemy is oh sehun.

Luckily for her he left the country one year ago.

Good news: they have got a new housemate...probably even two housemates to have around once Sera's parents go abroad for days as a part of their job.

Bad news: her worst enemy is back.

Worse news: he is back to torture her.

But the worst news of them all: he is their new housemate.