In only their second outing, the Three Investigators are hired by a friend of their patron, Alfred Hitchcock, to find his missing parrot. The boys soon discover that his parrot was one of a group of seven, trained by their former owner to each repeat a specific message. The focus of the investigation shifts from finding the single lost parrot to discovering the secret behind these cryptic messages.

The boys aren't the only ones who want to hear the dead man's secret. Others, including an infamous French art thief, Huganay, have also concluded that the messages are the key to locating a particularly valuable hidden item.