American Oscar Harvey opens the trunk of his hosts' car and finds the body of a woman, beaten and bloody. But let's start at the beginning. Kate and Mannix O'Brien live by Curragower Falls in Limerick, in a lovely house they can barely afford. Their autistic son Fergus is bullied at school, and their daughter Izzy blames herself, wishing she could protect him. Kate decides that her family needs a vacation, and is convinced her luck's about to change when she spots a gorgeous Manhattan apartment on a home-exchange website. Hazel and Oscar Harvey and their two children live on Manhattan's Upper West Side. Though they seem successful and happy, Hazel has mysterious bruises, and Oscar is hiding things about his dental practice. They, too, need a change of pace. Hazel has always wanted her children to see her native Limerick, and the house swap offers a perfect chance to soothe two troubled marriages. But this will be anything but a perfect vacation. And the body in the trunk is just the beginning.