30 Days ~ Life with My Sister v1.0 by PillowCase - Adult Sex Game

The protagonist, who has been living alone in his parents' apartment for a year, suddenly receives a phone call from his parents with unexpected news. His younger sister has decided to attend school in town, and since you don't pay rent and have an extra room anyway, he is told to let her live with him without complaint. It is a good thing for the protagonist to be able to live under the same roof with his favorite sister, isn't it?