It is 1941. On the western tip of Cornwall, Leo, an only child, has invited his bereaved schoolfriend, Justin, to stay for the summer. Neglected by his wayward mother, and desperate to forget his father's death in action, Justin is soon smitten with Leo's mother, Andrea.Unknown to Andrea, Justin finds danger the best antidote to unhappiness. One night he browbeats Leo into joining him on a hazardous night swim to investigate a supposed 'spy ship' moored off the coast. The outcome is as disturbing for the boys as it is momentous for Andrea. Her overworked husband Peter blames the whole episode on the adventure stories the two boys love - books he loathes for their simplistic depiction of heroism.Yet when Justin stuns Leo with a revelation about his mother that threatens his father's happiness, Leo acts so decisively that Peter is forced to redefine his most cherished beliefs..
