Frank and Joe Hardy introduce their new mystery.

Frank angers Joe by spending all day on the phone with girls so Aunt Gertrude sends Joe on an errand with Iola.

Joe finds muddy footprints and fresh milk while Iola is warned to stay away from the property. Iola alerts Frank.

Joe searches the house and barn. Frank arrives but is spooked while looking for Joe.

While running from the farm, Frank and Joe encounter someone who becomes their new client. Later, they discover what is to become of the animals.

Frank and Joe return to the farm but are soon joined by a man in a truck.

The boys conclude that someone, maybe even a ghost, has been helping the animals. They create a plan to catch a ghost.

The boys' plan to catch the ghost works too well and the ghost wants to know what the boys know about the animals.

Eric finds the boys at the farm and worries he's getting them in trouble. But before they leave, the ghost finds Lacey's will and sneaks it to Joe. Back home, Mr. Hardy and Mr. Binks try to determine its authenticity but Joe isn't so sure.

The boys are brought in after the police discover they removed the animals to avoid them being slaughtered.

Lacey confesses everything to get Frank and Joe out of trouble.

Iola discovers Lacey has had something all along to save his farm.

The animals get loose on the men who came to collect them, just in time to - as the boys and Iola arrive with the proof Lacey can afford his taxes to save them

Lacey has a fortune in old books and manuscripts. Ample money to take care of him and his animals for the rest of their lives.