During spring break at the end of her first year of high school, Ito learns she has to move because her mother is getting remarried. What she didn't expect is suddenly gaining four younger stepbrothers under the same roof.

Determined to get along with her new family, Ito does her best to adjust, but the eldest brother, Gen, is distant and hard to read. Yet as they spend more time together, she starts to see glimpses of kindness behind his cool exterior.