 Diane s ex-fiancé, Sumner Sloan, returns to Cheers looking for Diane. He has come to apologize and suggests to Diane that they go out for dinner so that she can meet his wife Barbara. She reluctantly agrees, but when Sumner mentions that Diane is welcome to bring any significant person in her life to the dinner, she does not mention Sam. Finding this out, Sam is hurt and offended, thinking that Diane is ashamed of him, especially in the company of brutally intellectual Sumner. Although she does eventually agree to bring Sam along, he suddenly realizes that he has agreed to a dinner with 3 intellectuals and that he will come across looking like an idiot. Cliff suggests that a good conversation piece with English professor Sumner would be Tolstoy s massive novel War and Peace, so Sam has 5 days between now and dinner to read the novel. Staying up for 5 days and nights, Sam finishes the novel just prior to dinner, however the 5 sleepless nights has physically and mentally taken its toll on him. To make matters worse for Sam, both Sumner and Diane announce for various reasons that War and Peace would not be the most stimulating dinner conversation, so his sleepless nights were for not. Sumner has shown up for dinner without Barbara, who is apparently ill. After dinner, one where Sumner and Diane have gotten into their old groove and Sam feels totally excluded, Sam confronts Sumner about his real intention, that of getting Diane back, and although Sam still wants her, throws her into Sumner s arms as he thinks they are a better match. Although Diane thinks Sam is off the mark, Sumner does confess that those were in fact his true intentions. In the end, Diane returns to Sam, the reason being that he read War and Peace... for her.