After taking a nap, Mirai is thirsty and Gekko refuses to buy her a drink. She notices a strange-looking potion on the table and chugs it despite Yuichi previously telling her not to touch it. The potion causes the person who consumed it to swap souls (thus switching bodies) with anyone he or she comes in contact with. The main cast spend the day inadvertently swapping bodies due to Mirai's carelessness.