When Iris Armstrong goes missing, her best friend Terry, wife, mother and all-round worrier, is convinced something bad has happened. And when she finds her glamorous, feisty friend, she's right: Iris is setting out on a journey that she plans to make her last. The only way for Terry to stop Iris is to join her, on a road trip that will take her, Iris and Terry's confused father Eugene onto a ferry, across the Irish sea and into an adventure that will change all of their lives. Somehow what should be the worst six days of Terry's life turn into the best.