The alternate reality was a parallel universe created in 2233 with the temporal incursion of the Narada, a Romulan civilian mining vessel under the command of Nero from the year 2387. The Alternate Reality differed from the primary reality in a number of capacities, including the attack upon the USS Kelvin, the launch of the USS Enterprise in 2258, and the destruction of the planet Vulcan by the Narada. (TOS movie, novelization & comic adaptation: Star Trek)
The Narada was pulled into a black hole and appeared in the year 2233. Nero launched an attack on the Federation starship USS Kelvin. The Narada was able to destroy the Kelvin with its powerful weapons. Crippled near Klingon space the Narada soon attracted the attention of the Klingons. A fleet led by Captain Kor of the IKS Klothos attacked. The Narada's crew did their best to repel the Klingons, but despite killing many could not hold back the stronger Klingon force. (TOS comic: "Nero, Number One")
Destruction of VulcanEdit
The Narada attacked Vulcan, destroying all of the Starfleet ships that attempted to intervene. Though the Enterprise crew tried to foil this plan, the Narada successfully drilled into the core of the planet and placed Red matter there, creating an artificial black hole at the core, which promptly consumed the planet. (TOS movie: Star Trek (2009))
Attack on EarthEdit
The Narada then attempted to destroy Earth in a similar manner, but through the actions of Captain Kirk and Spock, an artificial black hole was created which then consumed the Narada. (TOS movie: Star Trek (2009))
The Enterprise engaged in a series of campaigns against the Klingon Empire, the Cardassian Union, and the Romulan Star Empire, going up against some of the most advanced starships of each. (TOS video game: The Mobile Game)
After stopping at the Aldebaran colony, the Enterprise prepares to leave our galaxy whent it intercepts a record-marker from the SS Valiant. Spock is able to analyze the memory banks, revealing an unknown force in the region that forced her captain to destroy his own ship.
Continuing its course to our galaxy's boundary, the Enterprise encounters an unusual force field known as the galactic barrier. Nine crewmembers die, and another is injured—Kirk's friend, Lieutenant Mitchell. The Enterprise also loses her warp capability.
Under the care of Leonard McCoy, Mitchell begins to exhibit unusual powers, such as levitation and telepathy. At a senior staff meeting in the briefing room, the crew agrees to maroon Lieutenant Mitchell on "another Delta Vega."
Arriving at Delta Vega I, Kirk and McCoy prepare Mitchell for exile when he attacks Kirk with a blast of energy from his hands. McCoy makes a split decision to knock him out with sedative. He is later beamed down to the planet, with Kirk and Spock, while Scott and Kelso search the facility for materials they need to restore the ship's warp drive.
Mitchell revives, escapes his force field, then stuns Kirk and Spock with the energy from his hands. He later meets Kelso, and forces his former friend to shoot and kill himself with his phaser.
Scott revives Kirk and Spock, telling them Mitchell has escaped and Kelso is dead. Kirk makes a command decision to confront Mitchell, ordering Spock to quarantine the planet and leave if he has not returned in three hours.
Awaiting him in the desert, Mitchell demonstrates his power of illusion to Kirk by transforming the landscape around them into the bar from Iowa. Returning the landscape to its original state, Mitchell forces Kirk to kneel before him and beg forgiveness for his failure and his humanity. As he does so, Spock comes up behind Mitchell and nerve-pinches him. Kirk oders Spock to stand back, then shoots and kills his friend.
Kelso and Mitchell are buried in space. Spock later joins Kirk in the briefing room, offering to play chess with him. Kirk accepts the offer, and Spock leaves for Engineering, leaving him alone in the briefing room.