Plot

The Mirror Universe saga concludes as Archer declares himself captain of a formidable starship from the future, while his alien crew launch a rebellion in a desperate bid to keep him from achieving ultimate power.

Archer and his crew have taken over the Defiant and soon find out the firepower of the vessel. The Tholian ships have no chance whatsoever. There's still one problem as there seems to be a saboteur on board. Two warp regulators are stolen and Kelby is found with a reptilian bite. After Archer takes care of the problem, the Enterprise travels back into familiar space. They interfere in a battle between the rebels and the Empire. Only the Avenger is left and Captain Archer has no trouble saving it. Admiral Blake is on board and is impressed by the ship. Archer gets the idea he isn't the one who will gain the credits for this victory and once again decides to take the matter into his own hands.—Arnoud Tiele (imdb@tiele.nl)

Archer and his crew have taken over the Defiant and soon find out the firepower of the vessel. However, the Tholian ships create a web over the opening of the dock to prevent the Defiant from leaving. Archer activates the Defiant and uses the ship to defeat the enemies of the Empire, including the internal ones in his crew. Then he heads to Earth with the intention to take over the power in a coup as Emperor. After Archer takes care of the problem, the Enterprise travels back into familiar space. They interfere in a battle between the rebels and the Empire. However, there is a final and unexpected betrayal that affects the fate of Archer and the Empire.—Claudio Carvalho, Rio de Janeiro, Brazil

Several Tholian ships then create a web over the opening of the dock to prevent Defiant from leaving. T'Pol and Tucker restore power to the weapon systems, allowing Defiant to destroy enough enemy vessels to escape the trap. They recover 47 survivors from Enterprise, and Tucker is ordered to restore power to the warp drive. T'Pol argues that the Defiant is designed to be operated by a crew of 400, and there aren't enough crew to work it. She wants to take DEfiant to Earth and Starfleet, but Archer wants to take it to the front lines to help win the war (The war is against alien rebels including Andorians, Vulcans, Tellarites etc whom the humans don't consider as equals).

Sato goes to the captain's quarters and finds Archer perusing the ship's historical records, which includes parallel universe information about Starfleet, the United Federation of Planets, and their service records. Archer is surprised to learn his counterpart is an acclaimed and distinguished explorer, diplomat and politician.

Ensign Kelby (Derek Magyar) is killed trying to repair the warp drive, and the crew discover, from Tholian slaves left on board, that a Gorn named Slar has sabotaged the ship (It stole critical components and as a result the Defiant is stuck at impulse). Archer, after hearing voices telling him to achieve more fame and honor, decides to lead an assault team (Many of Enterprise's crew are killed in the ensuing hide and seek battle) and kills the Gorn (The Gorn had contacted Archer and said that it wanted a shuttle to escape, but Archer refused until the Gorn restored the ship's warp drive). Tucker is able to repair the warp drive and the ship then leaves to rendezvous with the ISS Avenger, arriving in time to save it from four rebel spacecraft (Archer destroys the Vulcan spaceship as well, despite pleadings from T'Pol to spare it). Avenger's commanding officer Admiral Black (Gregory Itzin) comes aboard for an inspection accompanied by his first officer, Soval (Gary Graham). After Black refuses Archer's request for captaincy of the new ship (Archer thinks that the Admiral is planning to present the Defiant to the Emperor himself), Archer disintegrates him with a phaser pistol.

Archer gives a speech to the officers of both ships, saying that they should move against Starfleet and the Empire. Soval and T'Pol meet, contemplating a future where alien species are respected and treated as equals. T'Pol says that Archer's moves would kill thousands of Vulcans as well, and she wants to stop him. they convince Phlox to join their movement (T'Pol convinces Phlox by saying that Archer wants to kill the emperor and rule Earth) and sabotage Defiant.

As the sole alien allowed to remain on board, Phlox succeeds in disabling the ship's systems (Archer captures T'Pol when she tries to transfer Defiant's specs to Starfleet and puts her in the brig). Soval, on Avenger, then attacks, but Tucker disables Phlox and restores power. Defiant destroys its attacker.

When Sato and Archer celebrate in the captain's quarters, Archer dies after being poisoned by Sato and we see that Mayweather is now in league with Sato. Reaching Earth on the advanced and powerful Defiant, Sato contacts Admiral Gardner (John Mahon), demanding his surrender and declaring herself "Empress Sato".