The Final Battle: Part 1

The Final Battle: Part 1 is the fourty-fifth episode and part one of the two-part series finale of Ben 10: Alien Force.

Plot
Myaxx informs Azmuth that someone has stolen the Ultimatrix, Azmuth's newest creation. Albedo has it and has completed the Ultimatrix in order for him to regain his original form but the Ultimatrix only has Ben's currently available aliens. Vilgax then appears out of nowhere (Possibly because he was there the whole time) and makes an alliance with Albedo, saying he doesn't want the Omnitrix anymore and just wants to kill Ben and take over his world.

Meanwhile, Ben has been kidnapped by Kraab, and Gwen and Kevin use Ship to get to Kraab's ship and rescue Ben. Kevin fights Kraab while Gwen goes find Ben. When she frees Ben, she sees that Kraab has put a special bracelet on Ben's wrist so he cannot transform into his aliens. Ben then attacks Kraab and steals his keys and frees himself of the bracelet. Ben then transforms into Big Chill to fight Krabb but soon he wrecks the ship's auto-pilot and are in an asteroid field (Which Kevin states he did not know they were heading for). Soon Ben transforms into Jetray to try to get the asteroids out of the way, but is forced to retreat when he fails to destroy a giant asteroid. The asteroid destroys Kraab's ship and presumably kills Krabb, but Gwen and Kevin save him (Kevin states that in his defense, Gwen  made  him save Krabb).

Kevin drops Gwen and Ship at Julie's house, while he and Ben watch a Sumo Slammers marathon. After leaving Ben's house, he runs into Albedo, who changes into Diamondhead and fights Kevin, then takes him back to his and Vilgax's hideout (But not before stopping for chili fries). Gwen walks home after she thinks that Kevin has gone missing and then sees Kevin's car wrecked, and covered with Diamondhead shards. She, like Kevin, runs into Albedo and is kidnapped by him as Swampfire. Albedo then attacks Grandpa Max as Spidermonkey, but Max escapes, so Albedo runs away as Rath. Albedo then records a broadcast to Ben's television, telling Ben that he has kidnapped Gwen and Kevin.

Ben then heads to Albedo's hideout, where he shows Ben the power of his new Ultimatrix by transforming into Ultimate Humungousaur. After being easily defeated by Albedo, Ben runs into Vilgax and his new Bioid army created by Psyphon, where he threatens to kill Gwen and Kevin unless Ben gives him the Omnitrix. Ben has no choice and surrenders the Omnitrix, using a voice command mode to decouple the Omnitrix from Humungousaur. Then Vilgax holds the Omnitrix into the air as a sign of victory.

Spells Used
Cherbome

Turbo

Major events

 * Albedo steals and finishes the Ultimatrix.
 * Vilgax and Albedo team-up to take the Omnitrix from Ben.
 * Albedo makes the first ultimate transformation into Ultimate Humungousaur.
 * Ben surrenders the Omnitrix to Vilgax.
 * Kraab makes his first appearance in Alien Force since Hunted

Characters

 * Ben Tennyson
 * Gwen Tennyson
 * Kevin Levin
 * Max Tennyson
 * Azmuth
 * Myaxx
 * Julie Yamamoto
 * Ship

Villains

 * Albedo
 * Vilgax
 * Kraab
 * Bioids

Aliens used by Ben

 * Big Chill
 * Jetray
 * Humungousaur

Aliens used by Albedo

 * Diamondhead
 * Swampfire
 * Spidermonkey
 * Rath
 * Humungousaur
 * Ultimate Humungousaur (first appearence, intentional test-drive transformation to prove the Ultimate feature works)

Trivia

 * Ben references Alien Force while watching Sumo Slammers. The version of Sumo Slammers that he watches is called, Sumo Slammers: Hero Generation. Hero Generation was the working title for Alien Force. It takes place 5 years after the original Sumo Slammers, with the villain from the original joining up with the hero, like in Alien Force. A reference to how some people think the original series was better, by saying that Hero Generation was all messed up and whatnot.
 * Kevin says that he can't stand Sumo Slammers, but in Kevin 11, he went and stole new Sumo Slammers games with Ben. He probably meant he couldn't stand Sumo Slammers: Hero Generation.
 * Albedo's transformation into Diamondhead was just a different version of Ben's Diamondhead transformation sequence, but with a red hue instead of green.
 * After he shoots Kevin in the back with diamond shards. we see he has the others in his back (After pulling one out) then after he charges Albedo with a crushed up car, the othe Diamondhead shards are not there, nor are there any hole from them.
 * When Albedo transforms into Swampfire, he does not select Swampfire nor does he slap the dial down, instead he spins, and transforms into Swampfire automatically.
 * After Swampfire puts gwen to sleep, you see he has four fingers, then a split second later he has five.
 * After Albedo gets hit with a frying pan (When trying to ambush Max) the handle is up, but when he is about to pull it off, the handle is down.
 * Just before Albedo transforms into Humongousaur, you can see he isn't wearing the Ultimatrix, but a red Omnitrix.
 * In this episode, Galvan Prime has been repaired. Which will eventually be known as Galvan Mark 2 in Map of Infinity
 * Gwen finally admits that Kevin is her boyfriend.
 * When Albedo transforms into Ultimate Humungousaur, the spikes on the Ultimatrix don't appear until after he gets consumed by the red light.
 * It seems that even an Omnitrix alien could defeat either Kevin or Gwen though Kevin possesses Osmosian abilities and Gwen posses Anodite's. It would take time though to do so as Kevin and Gwen are good fighters respectively.
 * Gwen used the Turbo Spell twice in this episode. Once to free Kevin from Kraab and second to deflect Swampfire's attacks.
 * This episode is similar to Back With a Vengeance, because in both episodes, Ben's rival (Kevin 11 in the classic series and Albedo in Alien Force) teams up with Vilgax to try and steal the Omnitrix from him and succeed.
 * After Albedo passes Lodestar, Humungousaur, and Echo Echo's holograms on the Negative Ultimatrix, Alien X's hologram was there, and the couplings were white/silver and so was the DNA scanner (The part underneath the hero selector).
 * This marks the second time Gwen used the Turbo Spell (the first was in Busy Box)
 * When Albedo puts the Omnitrix core into the Ultimatrix, the wrist couplings are not there, but instead his arm is there, then when the symbol changes from green to red, the wrist couplings are there.