Where is Helen? Margy and Rose arrive home to find the apartment empty, with no sign of Helen. As the hours pass into days, the frantic girls desperately seek answers. The last time anybody saw Helen, she was headed to Mr. Bullard's art shop at his request. Curiously, the art shop was robbed of an extremely valuable painting at about the time that Helen would have arrived.

The girls feel that there must be a connection, and so Margy and Rose interview Mr. Bullard as well as the owners of the stolen painting. Finally, the girls obtain the clues they need, but it is a race against time to locate Helen before she is lost forever.