Former major league baseball player Moe Berg lives a double life working for the Office of Strategic Services in World War II Europe.

Waffen-SS officer Otto Skorzeny (1908-75) became famous for his participation in daring military actions during World War II. In 1947 he was judged and imprisoned, but he escaped less than a year later and found a safe haven in Spain, ruled with an iron hand by General Francisco Franco. What did he do during the many years he spent there?

The (O)ffice of (S)trategic (S)ervices' Cmdr. Brady (Patric Knowles) forms Operation "Applejack" (based on a composite of actual incidents during WWII) and sends Lt. (j.g.) Philip Masson, U.S.N.R. aka John Martin as spy Philippe Martine (Alan Ladd) along with Miss Ellen Rogers posing as her college roommate, Madame Elaine Duprez (Geraldine Fitzgerald) and Robert Bouchet, Tech Sgt., A.U.S. as Albert Bernardito (Richard Benedict) to acquire secret Nazi plans. After nearly getting caught they succeed and get new identities. However they discover a secret that could change the war and risk their lives to get the information back to London before it jeopardizes their lives.

OSS agent, working with the French underground, ambushes Nazi convoy with high-ranking general, who escapes. Later they take him from a Nazi prison and smuggle him to England.

Near the end of World War II, a secret American raid on an enemy transportation hub goes very wrong when a turncoat warns the enemy. Led by Capt. Webster Carey, the mission causes the deaths of many bystanders -- among them, Carey believes, his Italian girlfriend, Giulia de Graffi. Back home, Carey stumbles across evidence that might uncover the identity of the informant. But, when he returns to Italy to get even, Carey is stunned by what he finds.