The son-in-law has to stay at his wife's parents' house due to a business trip. The mother-in-law, who is currently single and in her fifties, feels a strange affinity with her daughter's husband whom she hasn't seen in a long time, probably because she is lonely every day. She naturally wants to have excessive contact with him, so she ends up having sex with him! The son-in-law cums inside his mother-in-law without his wife's knowledge!