Barry and Eileen, a middle-aged couple, live in a sexless marriage. Barry, feeling over-mothered and desperate for an escape, begins an affair with an opportunistic test subject at his cosmetic research company, while testing a new skin cream derived from snail mucus. Barry's mood and vitality improves, but his change in behavior arouses Eileen's suspicions. As she uncovers his infidelity, Barry begins a physical transformation. When Barry meets his mistress for another rendezvous, she is disgusted by his appearance. Hurt, scared and in deteriorating physical condition, Barry returns to Eileen seeking her help and forgiveness. At first furious, Eileen comes to realize her situation. Barry, helpless and trapped, is completely at her mercy. She resumes her mothering position, and exacts a unique revenge on Barry.
