Would you swap houses with a family of strangers? The price you pay might be greater than you think . . .

Sophie and Andrew are looking for relief from the daily grind - if not each other - so when a friend puts them in touch with William and Beth, newlyweds looking to swap houses for the summer, it seems a solution of sorts. They find themselves in a stylish Connecticut home, a stone's throw from New York, while William and Beth take over their lived-in family house in South London, ideal for spending time with William's teenaged sons.

The weeks away work an unexpected magic for Sophie, who begins to find a sense of happiness . . . although Beth has no such luck and, no longer the centre of William's world, grows increasingly miserable. And so the two marriages - one crushed by the weight of years, one shiny and new - slide into reverse.

The intertwining of these lives and hearts begins to have dramatic consequences none of them could have foreseen . . . and all are powerless to stop.