From the attic of a dilapidated English country house, she sees them -- Cara first: dark and beautiful, clinging to a marble fountain of Cupid, and Peter, an Apollo. It is 1969 and they are spending the summer in the rooms below hers while Frances writes a report on the follies in the garden for the absent American owner. But she is distracted. Beneath a floorboard in her bathroom, she discovers a peephole which gives her access to her neighbors' private lives.

To Frances' surprise, Cara and Peter are keen to spend time with her. It is the first occasion that she has had anybody to call a friend, and before long they are spending every day together: eating lavish dinners, drinking bottle after bottle of wine, and smoking cigarettes till the ash piles up on the crumbling furniture. Frances is dazzled.

But as the hot summer rolls lazily on, it becomes clear that not everything is right between Cara and Peter. The stories that Cara tells don't quite add up - and as Frances becomes increasingly entangled in the lives of the glamorous, hedonistic couple, the boundaries between truth and lies, right and wrong, begin to blur.

Amid the decadence of that summer, a small crime brings on a bigger one: a crime so terrible that it will brand all their lives forever.