Guest, the eldest son, has supported his three younger brothers ever since their parents left. The Hagino household, where he is constantly jerked around by his brothers who adore him, was greeting another typical day. Soon, the youngest, Maron, returns home full of energy after school.

The once quiet house instantly becomes lively with Maron's voice. Today was the start of another noisy time where Guest would be at the mercy of the three brothers.