It's the summer of 1939. A private girl's school - the Augusta Victoria College in Bexhill-on-Sea - is run with loving care by the spinster Miss Rocholl (Judi Dench). But the 'finishing school' is unusual, in that all its teenage students are German. Indeed, they are the offspring of prominent Nazis. When half-German English teacher Thomas Miller (Eddie Izzard) applies for a suddenly vacant position, he is taken on to share the teaching duties with Rocholl and Ilse (Carla Juri). But in snooping into the activities going on there, he finds mystery and danger.