 Nicky Renzi, a diminutive fourteen-year-old, finds the loot from a robbery in an abandoned house and consults Perry Mason about the legality of keeping it. His grandfather, Gramp Renzi, is adamant about reporting it to the police, but then Gramp is charged with grand theft. When the brains of the robbery, Frank Anderson, is found dead, Gramp is charged with murder. Perry ultimately depends on ears more than eyes to solve the riddle.