When invited to a christening, bohemian free-spirit, Arima, finds herself reunited with her past. As she relies on the kindness of her old friend Sarah and husband Lawrence for a place to stay, Arima discovers an unhappy truth in their marriage and offers to return their kindness by making a life-changing promise. But can any good come from the promise? Can Sarah and Lawrence trust Arima and can their marriage remain strong through such a testing time?