The protagonist has Hasukawa Ai, the most beautiful girl in the school as his lover and is leading a steady life. But one day, in the next room of the apartment where he lives, a beautiful blonde girl Helen, moves in.

Due to Helen's friendly personality, the two of them quickly become friends with each other. However, when Helen learns that the protagonist has a girlfriend, she begins to make a move on him aggressively.

By stealing someone else's lover, Helen satisfies her lust.

And with her charm, the lust of a young man begins to overflow.