On the first day of the remarriage, my stepsister glared at me. "...I'm not up for playing family."

A daily life of living together with a sullen stepsister, Nanase Yui, that suddenly began due to their parents' remarriage. She coldly rejects playing family and pushes him away with a languid air in her loungewear, but as they spend time under the same roof, the clumsy domesticity and true feelings hidden behind her curt attitude begin to spill out.