After the Enterprise is diverted to the Romulan planet of Romulus, supposedly because they want to negotiate a truce, the Federation soon find out the Romulans are planning an attack on Earth.

To save Earth from a destructive space probe, Kirk and his fugitive crew go back in time to 20th century Earth to recover two humpback whales, who are the only Earth beings who can respond to it.

On the day of James Kirk s birth, his father dies on his ship in a last stand against a mysterious alien vessel. He was looking for Ambassador Spock, who is a child on Vulcan at that time, disdained by his neighbors for his half-human nature. Twenty years later, Kirk has grown into a young troublemaker inspired by Capt. Christopher Pike to fulfill his potential in Starfleet even as he annoys his instructors like young Cmdr. Spock. Suddenly, there is an emergency at Vulcan and the newly commissioned USS Enterprise is crewed with promising cadets like Nyota Uhura, Hikaru Sulu, Pavel Chekov and even Kirk himself thanks to Leonard McCoy s medical trickery. Together, this crew will have an adventure in the final frontier where the old legend is altered forever even as the new version of it is just beginning.