Billy (Michael Douglas), Paddy (Robert De Niro), Archie (Morgan Freeman) and Sam (Kevin Kline) have been best friends since childhood. So when Billy, the group's sworn bachelor, finally proposes to his thirty-something (of course) girlfriend, the four head to Las Vegas with a plan to stop acting their age and relive their glory days. However, upon arriving, the four quickly realize that the decades have transformed Sin City and tested their friendship in ways they never imagined. The Rat Pack may have once played the Sands and Cirque du Soleil may now rule the Strip, but it's these four who are taking over Vegas. Written by Production
The next morning, Paddy confronts Billy at the pool and tells him he does not love Lisa like Paddy loved Sophie and that the wedding must be stopped. As Lisa and her bridesmaids arrive, Paddy pushes Billy into the pool and tells Lisa that Billy is calling off the wedding. Billy and Lisa talk it out and Lisa leaves with her bridesmaids. As the guys pack up to leave, Billy comes to terms with his age and admits his fear of getting old and being alone. They come together as friends again and tell Billy to go see Diana. Billy shows up at the lounge where Diana is singing and reveals his feelings for her. The guys say their goodbyes to Dean and Lonnie and finally decide to crack open the old bottle of scotch for a final toast..