 Wealthy dowager Mary Eldridge wants to make a $300,000 contribution to her alma mater over the objections of her lawyer. She leaves the decision of how the money should be used to the students, and led by young Nancy Drew, they want it spent on a swimming pool. Although taken aback by the request the old woman agrees. Before the donation can be formalized, Eldridge mysteriously leaves town, but Nancy does believe her lawyer s facile explanation. After witnessing the kidnapping of a local doctor, she discovers a conspiracy to coerce the old woman to sign over her fortune to a criminal ring specializing in swindling wealthy senior citizens. Nancy and boyfriend Ted Nickerson utilize a carrier pigeon, low flying airplane observation, and disguises to free the dowager from the sanitarium where she is being held.