Complex sentence: The three villains later return in a "lost season" episode from 1983 titled "Return of the Phantoms" in which they hijack an alien's time-space conveyor and go back in time to Smallville and attack Superboy to prevent him from becoming Superman.
Split into simpler sentences: The three villains later return in a "lost season" episode from 1983 titled "Return of the Phantoms". Here they hijack an alien's time-space conveyor and go back in time to Smallville and attack Superboy, in order to prevent him from becoming Superman.