In light of her reconsideration of Sam's marriage proposal, Diane comes back to work at Cheers as she knows it's only time before Sam's will will once break down and he'll ask her to marry him again. Sam does let her work there only so that she'll see the bevy of babes he will be dating. He flaunts his next date, a romantic weekend getaway to the Cape, in her face. Despite his original date, Rhonda, canceling on him, he manages to get a replacement date, Vicki, who also ends up canceling on him once they get to the Cape because of an illness in the family. What's worse for Sam is that Diane shows up at the same inn just to rattle him. Wanting to show Diane that he is having a good time with anyone but her, he clandestinely sends Vicki off on her way by herself while hiding in his and Vicki's room supposedly with her. Diane however finds out that Vicki has been called away and does whatever she can to expose his lie without directly coming out and saying so. As Sam and Diane continue with their respective ploys at any cost, they may come to a realization of what their "I'll show him/her" behavior really means.
—Huggo