Tachibana and his wife Hinata lead a happy married life, recognized by both themselves and others. Every morning, Hinata lovingly sees her husband off to work. One day, a female insurance saleswoman named Yui visits Hinata. Since Hinata is already covered under her husband's insurance, she declines Yui's offer, but Yui forcefully pushes her way in by offering a free gift. To her surprise, the gift turns out to be a vibrator, and Hinata finds herself gradually seduced by its sensations. Following Yui's persuasive words, she ends up signing an insurance contract. Slowly but surely, Hinata's heart begins to waver.