Tamsin and her best friend Michelle have been inseparable since they were teenagers. Even now they spend all their time together, along with Patrick, Michelle's handsome husband. So when Tamsin hears a rumor that Patrick is having an affair, she is furious and plots a scheme to catch him in the act, using her assistant Bea as live-bait. It should be fool proof. After all, Tamsin can trust Bea with anything, or can she?