The corrupt Emperor Tiberius forces his bravest general, Marcus, to subdue the monstrous Cyclops that has been decimating the countryside. Once the Cyclops is brought to the dungeons, Marcus is forced to fight in the gladiatorial games. Eventually, he and the Cyclops become allies and they fight together to defeat the corrupt Emperor and his evil nephew, along with the beautiful barbarian Barbara.

Truman Capote (Hoffman), during his research for his book In Cold Blood, an account of the murder of a Kansas family, the writer develops a close relationship with Perry Smith, one of the killers.