In 2263 an escape pod was picked up by the Starbase Yorktown. It's occupant was found to be an unknown alien who's language was unknown to the universal translator. After some work basic communication was achieved and she reported that the rest of her crew was stranded on the planet Altimid on the far side of the Necro Cloud nebula. 
Captain Kirk and the crew of the USS Enterprise where dispatched to investigate. On arrival at the planet a large diffuse object was detected approaching the ship. As the range closed and more accurate scans were made it was discovered that the ship was actually a vast swarm of small ships. Captain Kirk ordered red alert just as the swarm broke formation and attacked. 
The Enterprise fired all weapons against the oncoming swarm but the shear numbers made any defence ineffective. The alien swarm attached the primary hull breaching it in several places. They also slammed into the deflector dish destroying it almost immediately. Kirk ordered the ship to warp to escape the attack but the swarm severed the nacelle pylons, rendering the warp drive useless. 
At this point breaching pods started attaching to the hull and alien troops bordered the Enterprise. The ships crew were armed and began defending against the intruders. It soon became apparent that the alien leader had breached the ships vault and retrieved an artefact, the Abronath, that had recently been placed there. Concerned by this Kirk put Sulu in charge of the bridge and went to investigate. 
Kirk is able to recover the Abronath and hides it in an unusual place. Scotty fixes the impulse engines and the Enterprise attempts to escape. Krall orders the swarm to separate the saucer from the engineering hull, disabling the impulse engines. Kirk orders the crew to abandon ship. 
The saucer without power enters the atmosphere and crash lands.