Two families arrive in Puerto Vallarta, Mexico, for a once-in-a-lifetime vacation. Jenna, who organized the trip for her husband's fiftieth birthday, is sure everything is going to be just perfect. Yet as the families settle in, their best friends suddenly seem like annoying strangers. Even Jenna's reliable husband, Peter, is sharing clandestine phone calls with someone. And her teenage daughter, Clem, is spending an awful lot of time with Malcolm, who has been expelled from school. Jenna's dream of the ultimate celebration begins to crack and then crumbles completely, leaving her wondering whom she can trust and whether her life is about to be changed forever.