Somehow you and Yuji can switch bodies. Because you guys fell down the stairs. You don't know how to restore your body at will. Together, you try to solve this mystery and try to return to each other's bodies. Sometimes your bodies come back and sometimes they are swapped again, this makes you two shy and awkward. Luckily Yuji is a polite, friendly and kind person. During the day, your bodies switch, but at night your souls return to each other's bodies. You guys hide this from people.