In the Otaki household, the father, Yoshio, is assigned to a long-term overseas posting… The mother, Hibiki, and her two sons (Haruki and Yuuma) will be living at home. As the father's absence continues, the eldest son, Haruki, vows to 'protect his mother,' developing strong feelings for her. 'I like you' this feeling lasts for a month… Yuma, the younger brother, sees this and feels a complex mix of emotions, gradually realizing his own feelings for their mother. The brothers clash over their respective desires, fight over their mother, reconcile with each other, understand each other, and seek each other out.
