Burbank, summer 1985. Young Howie and his friends have lost a baseball belonging to Howie's father. It's a unique baseball in that it has Babe Ruth's autograph. Kate and George determine, through mathematical and physical laws, that the ball entered a house. Apparently Mrs. McGregor left her door open when she left for the store. So the valuable baseball is in Mrs. McGregor's house. When Kate and George call her the next day, they learn her house has been stolen.

Los Angeles, 1986. A grocery store is robbed of 20 pounds of bananas, the first of several heists apparently done by a gorilla. When the L.A. Zoo reports a gorilla missing, Kate and George are convinced he is the guilty party. Only the gorilla's friend, a teenage girl named Jane, stands to the gorilla's defense.

Santa Monica, 1986. After the Mathnetters help estimate the crowd at a parade honoring rock star and Burbank native son Steve Stringbean, they get word Stringbean has been kidnapped. His buddy Rimshot helps Kate and George immensely on the pursuit of the kidnappers. One strange lead is a badly-written march called 75 Trombones.

Los Angeles, May 1986. George Frankly comes back from a week in the Great North Woods. He has just heard of a robbery at the Next to the Last National Bank three days before. When he and Kate look at the bank's videotape recording of the robbery, they see the impossible: George is doing the heist. Evidence piles up against George as his preliminary hearing looms. George knows he is innocent, as does Kate. But can they prove it?

Glendale, 1986. Three truck drivers call within six hours to report that their dump trucks full of dirt have been stolen. Initially, this ""Case of the Missing Dirt"" turns up a long-lost tale about Merle Fish, the man who pulled off the Finks Armored Truck Robbery in 1965. Rumor had it he had an accomplice who took the money and left the country. This is all explained in a book written by the fishy Norman Mailbag.

L.A. County, April 1985. Two crimes start separately, but merge a few days later. Multi-talented Hans Ballpeen is kidnapped for one of his special skills. Before they can bear down on this case, Kate and George must help with the delivery of an oak hamburger to the mansion of tycoon Orson Kane. Within a day, Kane reports that one of his prized possessions, the Despair Diamond, has been stolen.