Johnny Casey, his two brothers Ed and Liam, their beautiful, talented wives and all their kids spend a lot of time together - birthday parties, anniversary celebrations, weekends away. And they're a happy family. Johnny's wife, Jessie - who has the most money - insists on it.
Under the surface, though, conditions are murkier. While some people clash, other people like each other far too much . . .
Everything stays under control until Ed's wife Cara, gets concussion and can't keep her thoughts to herself. One careless remark at Johnny's birthday party, with the entire family present, starts Cara spilling out all their secrets.
In the subsequent unravelling, every one of the adults finds themselves wondering if it's time - finally - to grow up?