While trailing the school French teacher, Professor Bedoin, hoping to catch him in a romantic interlude, Lillian Harding and Katherine Thompson, students at the exclusive Lakeside School for Girls, follow him to Angel's Roost, a gambling joint and learn that he is a regular player there. Chance Landon, the manager and henchman of a mysterious and unseen owner, induces the girls to play on credit. Lillian, the younger of the two, falls in love with Chance, and over a period of days, writes him several passionate love letters. When the girls have lost several thousand dollars at the crooked roulette wheels, Chance uses the letters as a club to make the girls steal valuable family jewels to make good their losses. The thefts bring insurance investigator Jimmy Parker to the school posing as a gym instructor. He stumbles upon a clue which makes Katherine confess her part in the crimes, and with this to work on, he sets out to trap the club's ring leader.