Best friends Joan and Patricia are teenage autograph seekers who spend most of their day bumping into and having tea with movie stars like Greer Garson and Walter Pidgeon. Based on disinformation from a meddling governess, Joan also devotes some time to working on the no-problem marriage of her parents.

Humble stamp dealer Otto Becker has little to do with international politics, so when he receives a surprise visit from his estranged twin brother and Nazi spy, Baron Hugo von Detner, his world is thrown into turmoil. Threatening Becker with deportation, Hugo forces him to use his shop as a front for espionage.