Lonely on a quiet night, a sister longs to be filled—until a lustful system appears and offers to send her back ten years. She wakes up in a more alluring body, and the system issues its tasks: masturbate in front of her brother, with extra rewards for oral. She rides her bike and deliberately presses close to him; at a red light she "accidentally" brushes against his already-hard reaction, and spends the whole day plotting how to finish tonight's tasks.