Cartwright's case starts off simple enough. Miss Stonewall, from the Mutual Trust Insurance Agency, wants him to track down a missing orangutan. The thing is, as Cartwright explains, he doesn't do orangutans. But when Stonewall offers him a large wad of cash for the job, Cartwright's suspicions are piqued. In his search for the orangutan, Cartwright stumbles across a rare green diamond, setting off a chain of events that lands him in the middle of a tangled web of conspiracies.