私をセンターにすると誓いますか？

Koichi Okuta pours every free hour and every spare yen into supporting Mizuki Natsuno, the least popular member of the idol group Melty Strawberry. When the two end up living under the same roof, Mizuki makes him an offer: get her to the group's center position, the spot Awayuki Shiroi has held so long that fans call her the Eternal Center, and she will marry him. Koichi takes the deal, and a fan and the idol he follows start working the same campaign from opposite sides of the stage.