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 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 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 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 Kraab, but Gwen and Kevin save him (Kevin states that in his defense, 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, 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 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 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.

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 (first re-appearance)
 * Julie Yamamoto (Cameo)
 * Ship

Villains

 * Albedo
 * Vilgax
 * Kraab
 * Bioids

By Ben

 * Big Chill
 * Jetray (x2)
 * Humungousaur

By Albedo

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

Spells Used

 * Cherbome
 * Turbo

Errors

 * In one scene, when Myaxx was talking to Azmuth, her neck was not covered by her suit.
 * After Albedo 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 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 don't appear until after he gets 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.
 * When Albedo steals the Ultimatrix even though the light is bad, you can see that he is not in Negative Ben form.
 * 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, we see no resistance (not even a stretch) from the seat belt.
 * 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).

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. A reference to how some people think the original series was better, by saying that Hero Generation was all messed up and whatnot.
 * 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 states that Gwen and Julie are going to be doing homework together meaning that the summer has ended and Ben and Gwen are now in 10th grade as of this episode.
 * Humungousaur's full transformation sequence is shown.
 * Ben's transformation into Humungousaur is the last transformation of the Omnitrix until it self-destructs by Ben using the voice command in The Final Battle: Part 2.
 * It's been stated that this episode doesn't take place on its airdate.
 * Grandpa Max and Albedo's skills are shown at their full potential because Albedo was able to defeat Gwen and Kevin in under a minutes worth of fighting despite the fact that they are good fighters and Grandpa Max was able to escape from an agile Spidermonkey. He was also the only person Albedo attacked that escaped.
 * Kevin says that he can't stand Sumo Slammers, but in Kevin 11, he went and stole new Sumo Slammers games with Ben. But, as confirmed by Dwayne McDuffie, Kevin liked the Sumo Slammers games, not the TV show.
 * Albedo's transformation into Diamondhead was just a different version of Ben's Diamondhead transformation sequence, but with a red hue instead of green.
 * 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.
 * 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 classic series and Albedo in Alien Force) teams up with Vilgax to try to steal the Omnitrix from him and succeed.