In this action-comedy the French fighter Jo Cavalier is charmed on the train at Hitler's Germany by the little boy Simon Rosenblum who requests his autograph. When it works out his adorable young fan can be just really a Jewish man in peril of persecutionhe risks his lone shot at Olympic glory to save Simon along with his family, helped only by way of a German officer-gentleman who became his friend in World War I, with an adventuresome escape to Switzerland, Nazi troops in their treats and braving hopeless odds in roller coaster-style.