Kirk leads a team with Spock and Uhura onto the planet in a small landing craft, where they are ambushed by Klingon patrols who order them to land. Every torpedo aboard Enterprise contains a human in stasis.Uhura leaves the landing craft to talk to the Klingons, but they don't care that Harrison is on their planet. Harrison is taken to the ship's brig, where he reveals his true identity as Khan, a genetically engineered superhuman awoken by Admiral Marcus from centuries of suspended animation to develop advanced weapons of war against the Klingon Empire.Spock chases down and pursues Khan through the city and is about to kill Khan, but Uhura stops him.Khan is knocked out and his blood is used to revive Kirk.Khan beams Kirk, Scott, and Carol back aboard Enterprise, but betrays their agreement by critically damaging Enterprise; however, Vengeance is disabled when the torpedoes detonate.With both starships caught in Earth's gravity, they plummet toward the surface.After Vengeance intercepts and disables Enterprise near the Moon, Carol reveals her presence aboard the ship.Marcus forcibly transports Carol to Vengeance before ordering Enterprises destruction, Kirk offers Khan and himself for the lives of his crew, but Marcus rejects Kirk's offer and orders Vengeance to attack.
Mc Coy discovers that Khan's blood has regenerative properties that may save Kirk.
However, Vengeance suddenly loses power, sabotaged by Scotty, who infiltrated the ship.
With transporters down, Kirk and Khan, with the latter's knowledge of the warship's design, space-jump to Vengeance.
Harrison then attacks Starfleet Headquarters in a jumpship during the emergency meeting about the situation, killing Pike and other senior officers.
Kirk disables the jumpship by throwing a rifle into one of its engines, but Harrison escapes by transporting to Kronos, the homeworld of the hostile Klingons.