Betsy Harlow is a hard-working maid in a boarding house. Her dream. however, is to be a detective, a dream she shares with her boyfriend Oscar, a delivery boy for a local grocer. One day a mysterious character named Harry Brent takes a room at the boarding house. Harry, seeing that Betsy is falling for his rather shady charms, persuades her to help him get a box of jewels owned by the Jaspers, an elderly couple who lives across the hall. It turns out that Harry is not quite who he seems; neither, however, are the Jaspers.