After a relationship settles into a comfortable routine, temptation can become hard to resist. A man who is seriously considering marriage grows suspicious when his girlfriend stops answering as many of his calls, so he asks the Sting operation to test her fidelity. His fears seem justified when Erena Yamamoto readily accepts a stranger's invitation and follows him back to the studio. Is she really cheating, or is she simply too easygoing? The final negotiation may even lead to penetration.