From The Perry Mason TV Show Book
Ever since her husband died, Reba Burgess has managed his mine, located in Burgess, California. When things were slow, Reba kept the business going by securing loans, using a shoe-box full of uncut diamonds as collateral.

So when Carl Bascom, a shady business associate of her late husband, claims to have a signed agreement giving him a half interest in the mine, Reba contacts Perry. Paul travels to Burgess to check up on Bascom and is there when the man's body is found, shot and floating in a mining sluice. When the murder weapon is identified as belonging to Reba, Perry takes up her defense.