Looking for the missing crew of a freighter commanded by Captain Merik (William Smithers), the Enterprise landing party beams down to investigate a civilization that is best described as a "20th century Rome." Once there, Kirk, Spock, and Bones are caught and imprisoned, and scheduled to face death if Kirk doesn't agree to turn over the rest of the Enterprise crew for use in their televised, deadly arena games.
"Bread and Circuses" is a well-executed but completely by-the-numbers episode of TOS. The show engages most every TOS cliché in the book, including Kirk getting a babe, the Prime Directive being assessed, a planet that is Yet Another Parallel Earth [TM], and the holding of The Big Three hostage, where they must use resourcefulness to escape their impending doom. Most interesting is the good work between Spock and Bones, which wants to ask the question of just which of their personal feelings their acerbic banter arises from.
Rhodes Reason makes a good antagonist as Flavius, but given the setting of a conveniently parallel Earth (an overused premise, to be sure) the whole setup is strikingly underutilized beyond its most obvious action sequences.