"To tone down the rating of the gangster Male Lead who is on the verge of turning dark!"

Baek Yi-hae, who was all alone in the world, finds herself possessed into a devastating, R-rated romance game. "Don't tell me... have I been marked by the gangster Male Lead?!"

Out of the blue, Yi-hae ends up moving into the home of the Seo family, a notorious mobster clan. To protect her peaceful and safe life as a mere "Extra of Extras," she must prevent the "Baby Gangster" Seo Do-gyeom from turning evil and ensure he reaches a Happy Ending.

Amidst a chaotic mix of school life, romance, and the game's threatening rules, the relationship between Yi-hae and Do-gyeom begins to shift in subtle ways...!

"Why are you only sweet to me?"

A sweet yet bloody survival romance where you can't let your guard down for even a moment!