Nina and Isabel are the closest of sisters, bound together since childhood by the devastating, sudden death of their baby brother. Against the backdrop of the hottest summer for a century, a drama of suspicion and betrayal unfolds. Bonds of love and shared history are stretched to the breaking point as Nina begins an illicit affair. Each sister claims to possess knowledge that could destroy the other. But who is lying, and who is telling the truth? As the past becomes alive and dangerous, it forces Isabel to commit a shocking, transforming act.