On Sigma Iotia II, a book left by an earlier Earth ship had shaped a culture based on Chicago gangsters, and Kirk joined the game to unite the rival bosses.
In 2268 the Enterprise investigated Sigma Iotia II, visited about a century earlier by the USS Horizon. The highly imitative Iotians had built their whole society on a book the Horizon crew left behind, a history of Chicago gangs in the 1920s. Rival bosses such as Bela Oxmyx and Jojo Krako fought for territory.
Kirk and Spock posed as gangsters themselves, with Kirk inventing a card game called fizzbin to distract his captors. He forced the bosses into a single government, with the Federation taking a cut. Spock and McCoy worried that the crew's own influence had done further harm, since McCoy left his communicator behind.