Returning to the Enterprise from an unsuccessful mission to ask the leaders of a planet for a possible mineral trade, Kirk, Uhura, Scotty and McCoy are being beamed up just as a freak accident hurls them into another reality, which still contains a USS Enterprise and a Spock and a Federation, but the other reality's versions are cruel and inhumane - the crew the alternate Enterprise is readying for a strike against the planet Kirk just left to take their mineral resources by force. Kirk and his landing party must try to cover their inexplicable identities and try to fit in, while stopping the savage alternate Enterprise from carrying its reign of terror any further.
