What would happen if... a guy and a girl who missed the last train decided to try "washing each other" in a mixed-gender hot spring...!? Two people—a friend, a coworker, and a senior-junior pair—who are slightly tipsy strip down, both mentally and physically, and wash each other's bodies in a mixed-gender hot spring, causing both to become aroused at the same time... Will they cross the line and end up having sex!? (DOD)