Dave(Vince Vaughn) and Ronnie(Malin Akerman), Jason(Jason Bateman) and Cynthia(Kristen Bell), and Joey(Jon Favreau) and Lucy(Kristin Davis) are close. The group used to include Shane(Faizon Love) and Jennifer(Tasha Smith), but they divorced and she's gone. Jason and Cynthia announce that their marriage is in trouble, and they beg their friends (and Shane's young girlfriend) to join them on a couples' retreat, at the package rate, on a tropical island. The others reluctantly agree, planning to play while Jason and Cynthia work on their marriage with an island psychologist. To everyone's surprise, the package is inflexible: each couple must participate in the couples' exercises. Soon fault lines appear in all four relationships. What's in store for each couple?