A daughter and her husband are staying at the wife's parents' house to prepare for the birth of their child. While the mother-in-law, Mako, is sorting through her daughter's belongings, she discovers an outfit worn by her daughter when she was a promotional girl. Out of curiosity, she tries it on. When the son-in-law returns home, he mistakes her seductive back for his wife and embraces her without thinking. The moment he realizes it's his mother-in-law, he can no longer contain his lust...