In 1942, Cork-born Kay Summersby's life is changed forever when she is tasked with driving General Eisenhower on his fact-finding visit to wartime London. The pair takes an immediate liking to one another and so begins a tumultuous relationship against all military regulations. Kay becomes known as “Ike's shadow,” but that does not stop him from using his influence to grant Kay US citizenship. When the US authorities discover Eisenhower's plans, Kay is forced to take desperate measures to hold onto the man she loves…