The Enterprise visits a planet whose culture is based entirely on one book about Chicago gangs of the 1920’s.
Intentionally amusing, with lots of heavy cheeze. Kirk and Spock especially have fun with the concept.
Highlights:
Scotty’s “heater” confusion
Spock’s helpful near-ruining of plan
Spock’s slight radio miscalculation
good guest acting
car hijinx
Kirk’s sudden accent/grammar changes
Lowlights:
one blatantly stupid Fizzbin contradiction