The Final Battle: Part 1

The Final Battle: Part 1 is the forty-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 available aliens. Vilgax then appears out of nowhere 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. 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 Kraab 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 Big Chill transforms into Jetray to try to destroy the asteroids, but is forced to retreat when he fails to destroy a giant asteroid. The asteroid destroys Kraab's ship, but Gwen and Kevin save Kraab (Kevin states, in his defense, that Gwen made him save Kraab).

Kevin drops Gwen and Ship at Julie's house, while he and Ben watch a Sumo Slammers marathon. After leaving Ben's house, Kevin runs into Albedo, who changes into Diamondhead and fights Kevin, then takes him back to his and Vilgax's hideout (after 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 diamond shards. She, like Kevin, runs into Albedo and is kidnapped by him as Swampfire. Albedo then attacks Max as Spidermonkey, but Max escapes, so Rath (Albedo) runs away. Albedo then sends 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 Ultimate Humungousaur (Albedo), Humungousaur (Ben) runs into Vilgax and his new Bioid army, where he threatens to kill Gwen and Kevin unless Humungousaur gives him the Omnitrix. Humungousaur has no choice and surrenders the Omnitrix, using a voice command mode to decouple the Omnitrix from him. Then Vilgax holds the Omnitrix high, posing his victory.

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 and Myaxx make their Alien Force debuts.

Characters

 * Ben Tennyson
 * Gwen Tennyson
 * Kevin Levin
 * Max Tennyson
 * Azmuth
 * Myaxx (first re-appearance)
 * Julie Yamamoto (cameo)
 * Ship

Villains

 * Albedo
 * Vilgax
 * Kraab (first re-appearance)
 * Vilgax's Biods (first appearance)

By Ben

 * Big Chill
 * Jetray (x2)
 * Humungousaur

By Albedo

 * Diamondhead
 * Swampfire
 * Spidermonkey
 * Rath
 * Humungousaur
 * Ultimate Humungousaur (first appearance)

Spells Used

 * Cherbome
 * Tur-bo

Errors

 * In one scene, when Myaxx was talking to Azmuth, her neck was not covered by her clothing.
 * After Diamondhead (Albedo) shoots Kevin in the back with diamond shards, he has the others in his back (after pulling one out), then, after he charges Albedo with a crushed up car, the other Diamondhead shards are not there, nor are there any holes from them.
 * When Albedo was about to turn into Humungousaur, he was wearing the Omnitrix instead of the Ultimatrix.
 * When Albedo transforms into Ultimate Humungousaur, the spikes on the Ultimatrix symbol don't appear until after he gets fully consumed by the red light.
 * When Albedo puts the Omnitrix core into the Ultimatrix, the wrist couplings are not there, but instead his arm is there, But when the symbol changes from green to red, the wrist couplings are there.
 * Kevin is shown to be wearing his seat belt when he crashed and even just before Albedo pulled him out of the car. But when Albedo does pull him (and throw him) out of the car, there is no resistance (not even a stretch) from the seat belt.
 * After Albedo passes Lodestar, Humungousaur and Echo Echo's holograms on the Ultimatrix, the couplings were white/silver and so was the DNA scanner (The part underneath the hero selector).
 * When Albedo is going after Max, Spidermonkey comes in through the roof of the Rustbucket, but when he turns into Rath and busts through the side, the hole on the roof is no longer there.

Allusions

 * 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. He also says that it is the end of the Sumo Slammers sequel series and it is the finale of Alien Force.
 * When Kevin is piloting Ship in the beginning of the episode, he makes a Star Wars reference by saying "Can't this bucket of bolts go any faster?", which is similar to what Princess Leia says in A New Hope.

Trivia

 * Kevin says that he can't stand Sumo Slammers, but in Kevin 11, he went and stole new Sumo Slammers games with Ben. However, according to Dwayne McDuffie, Kevin liked the Sumo Slammers games; not the TV show.
 * Albedo's transformation into Diamondhead was the same sequence as Ben's but red instead of green.
 * By this episode, Galvan Prime has been repaired.
 * This episode is similar to Back With a Vengeance, because in both episodes, Ben's rival who also has his powers (Kevin 11 in the original series and Albedo in Alien Force) teams up with Vilgax to try to steal the Omnitrix from him and succeed.
 * When Ben is watching Sumo Slammers on the TV the sumo on the left is very similar to Grandpa Max in Game Over from the original series.