Since childhood, Kwon Som has felt a strange, nauseating sensation whenever he sees Han-geon. Despite their similarities, these two very different people always end up fighting whenever they meet. After their parents marry, they become part of the same family, and new rules are introduced:

- Rule One: Go to and from school together.
- Rule Two: Hug for 30 seconds before entering the house.

This creates frequent moments where they are forced to hug each other, and due to Geon's provocations, they begin to kiss regularly...
"Shall we do it, then? I've already given you a chance to back out."

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