Finally moved into my long-awaited one-man dormitory after graduation! Out of nowhere, an unknown woman suddenly showed up! Apparently she's going to be my new sister soon. It seems like our parents decided to remarry without telling us, resulting in this step-sister. Moreover, since their house is close by, she occasionally visits to help each other out. She agreed to tidy up my room, but when she found my AV collection, she couldn't resist watching them! Now that we're technically family, my step-sister has become extremely aroused and wants to have sex with me! Who would've thought that someone I considered a stranger just yesterday would turn into my lustful stepsister today?