It is World War 2 and brothers George and John and their sister Eva are each fighting in their own way. Secret agent George is parachuted into Slovakia in an Operation codenamed Zinc, John breaks codes at Bletchley Park, while Eva is stranded in enemy-occupied Hungary.

Based on the extraordinary real-life stories of Sue Klauber's father, uncle and aunt, she wrote Zinc for her son to celebrate the full and heroic engagement of their North London Jewish family in the fight against tyranny.