The girls from Farringdon High have a picnic in the country, and during the picnic, two unkempt men arrive and ask for food. They have a suitcase with them from which comes a strange wailing noise. Judy is intrigued and wonders what kind of device is hidden in the suitcase. Later, Judy and Honey are accidentally left behind when the buses leave the picnic grounds. As they walk along a country road, they encounter a man lying in a ditch with a suitcase next to him. Judy feels certain that this man is somehow connected to the other two men and that the suitcase is the same suitcase. Judy and Honey are rescued by Peter and Horace, who also take the man home to his family. Judy learns that his name is Brady, and when she meets a new neighbor, Selma Brady, she feels certain of a connection. Judy travels with Selma to help clean house for her grandparents wedding anniversary. She once again meets the strange man from the ditch and becomes involved in a new and dangerous mystery.