A large tank is travelling through Bellwood. It is smashing over cars and being chased by police. Ben, Gwen and Grandpa Max find it and the tank begins growing spider-like legs to begin chasing them. They retreat to under a tunnel where their tires get destroyed. Grandpa gets out to fight it and tells Ben and Gwen they can't fight on a school night.
They both get out and Ben transforms into Upgrade and gets ready to fight. Gwen tries telling him it needs a spell to be destroyed and she begins fighting with Ben. Upgrade finally merges with the tank but it overcomes Ben's power. Gwen uses a spell on it and the robot falls apart. Then Upgrade transform back and the Omnitrix begins glowing pink, after being affected by the spell.
Ben is in an odd green world flying around on his hoverboard. He tries to find Grandpa Max but is attacked by Heatblast, followed by his over 5 aliens and Way Big. Then Way Big tells Ben he wants homework and Ben wakes up in class and is hassled by his teacher. Cash finds Ben at his locker and shoves him in. Ben tries to transform into Four Arms but instead becomes Heatblast, then he busts out.
Ben is in his room as Heatblast and Carl and Sandra are asking where he went. After he transforms back, he says he was looking for his underwear and they question him about the Heatblast footprints on the floor. Ben gets grounded. That night, Ben is studying. He says he wished his work would just vaporize and the Omnitrix vaporizes his laptop.
He calls Gwen about it but Tetrax appears, telling Ben that Azmuth wants to speak with him. Ben goes with Tetrax and is beside his ship when he flies off. But a blue To'kustar attacks them. Ben turns into Way Big but accidentally transforms into Stinkfly. He goes to attack the Evil Way Big after Tetrax explains that if you hit it on the fin it will become paralyzed.
Then he transforms back and is hanging onto it. He tells the Omnitrix to recharge, then it does and it destroys the To'kustar. Ben goes flying with Tetrax to find Azmuth. Tetrax puts a special setting onto the Omnitrix but Ben is unaware of what it is. He is shot out of the ship by accident. Ben becomes Diamondhead to break the fall.
Grandpa and Gwen are searching for Ben. They stop where Ben fought the To'kustar. Tetrax lands and tells them that he must tell them something. Ben is walking as Diamondhead. The Omnitrix begins to time out and Ben is happy that he will be able to catch a ride without freaking out the driver. Then he transforms into Four Arms because of the setting Tetrax put the Omnitrix into.
Retaliator then appears and begins attacking Four Arms. Retaliator reveals that he messed up Tetrax's ship, causing Ben to be shot out. Ben asks if he messed up Azmuth's ship too, making him late. Retaliator begins getting nervous by the mention of Azmuth. Ben manages to throw him away he transformed and transforms into Upgrade.
Retaliator comes back and tries to attack Upgrade before realizing he wasn't the Tetramand that he had originally been attacking. Upgrade tries to sneak away but he is attacked by Retaliator again and they teleport to Rio De Janeiro. After fighting more they are teleported to Egypt. Ben becomes Stinkfly and manages to escape.
They are flying through Bellwood and Ben becomes Heatblast. Retaliator captures Heatblast but he transforms into Grey Matter and escapes. Gwen, Max and Tetrax are talking when they find Azmuth's ship with a huge hole in it. They watch the log and find that the To'kustar attacked Azmuth's ship. Retaliator teleports in and tells them Azmuth is dead, then shows them the To'kustar attacking.
He begins asking for To'kustar but they try to explain it wasn't To'kustar attacking them. They trap Retaliator into a wall and sets the ship to self destruct. Grey Matter runs down his street and to his house where Sandra and Carl find him. Sandra begins attacking him but Grey Matter jumps on her head. She throws him outside. Grey Matter becomes Diamondhead, and Sandra passes out and Max shoots Carl knocking him out.
Tetrax and Gwen come out and Tetrax takes the setting off Ben's Omnitrix. Retaliator appears and attaches Ben to a rope. Ben transforms back to human and tells Retaliator to explain his connection to Azmuth. At the mention of Azmuth the Omnitrix begins glowing and teleports Ben, Gwen, Tetrax and Retaliator into a weird city.
Ben and Retaliator are in a forest of diamond shards. Ben asks where his Omnitrix is since it was missing from his wrist. Suddenly a bunch of Lepidopterrans begin attacking them. Gwen and Tetrax are trying to find where they are and Gwen says they are in the Omnitrix. There is thunder and Gwen questions why there would be thunder on a sunny day.
Then Tetrax says it's not thunder, then a bunch of Vulpimancers attack. Gwen uses a spell and they disappear. Ben is with Retaliator again and he tries to find out who the To'kustar was. Retaliator says that aliens don't fall from the sky. Then Gwen and Tetrax fall from the sky. Tetrax says they are on Petropia but Gwen explains it is a simulation by the Omnitrix.
Gwen captures Retaliator in a mana bubble where Retaliator explains that he is Azmuth's father. They begin asking about the To'kustar. Ben and Gwen are flying around on a mana platform. They find Tetrax and Retaliator fighting the To'kustar. Gwen casts a spell on Retaliator to make him teleport them out. They all teleport out, including the To'kustar.
Retaliator chases after the To'kustar. Ben tries to transform but the Omnitrix transforms his mom into Heatblast and his dad into Wildmutt. They attack Ben, Gwen, Max and Tetrax. The two figure out that the Omnitrix had transformed Azmuth into the Evil Way Big. They are in a mana bubble while Sandra tries to destroy the bubble.
She is finally successful but Tetrax puts up a diamond shield. Ben becomes Way Big and begins attacking the Evil To'kustar. Ben manages to knock him down but Retaliator attacks Ben, thinking he is the Evil To'kustar too. The Evil To'kustar gets up and Ben and Gwen try to explain to Retaliator that the Evil To'kustar is Azmuth.
They continue fighting and Ben tells Retaliator to stop Evil To'kustar you have to aim for the fin, so Retaliator does and hits Ben. Ben transforms to normal and Gwen casts a spell on the Evil To'kustar. Azmuth manages to capture Ben, Gwen and Retaliator, then uses Retaliator to fix the Omnitrix. Azmuth tells Retaliator he should stay away from the Mechamorph Armor because it makes people extremely aggressive, then he takes off Retaliator's armor, revealing a regular Galvan.
Ben asks for Azmuth to turn his parents back to normal. Gwen and Ben use the Omnitrix to transform them back to normal and they let Ben go on a fishing trip. Azmuth and Retaliator then leave. Azmuth tells Ben and Gwen to stop arguing about who destroyed the Rustbucket. Azmuth wears the Mechamorph suit and fixes the Rustbucket. The movie ends with Ben, Gwen and Max on another road trip and being attacked by Dr. Animo and his giant frog.
- Ben Tennyson
- Gwen Tennyson
- Max Tennyson
- Tetrax Shard
- Carl Tennyson
- Sandra Tennyson
- Cash Murray
- Ben's Male Teacher
- Ben's Girl Classmate
- Ben's Boy Classmate
- Upgrade (2x; second time unintentional)
- Heatblast (2x; first time accidental transformation, selected alien was Four Arms; second time unintentional)
- Stinkfly (2x; first time accidental transformation, selected alien was Way Big; second time unintentional)
- Diamondhead (2x; second time unintentional)
- Four Arms (unintentional)
- Grey Matter (unintentional)
- Way Big
- In Ben's dream, Ben doesn't have the Omnitrix for a few seconds.
- After Azmuth changed back, the time of day changed too.
- When Upgrade transformed back into Ben, the Omnitrix didn't glow red.
- The Omnitrix has two buttons to activate the dial throughout the whole movie.
- Way Big's Omnitrix symbol is green.
- When Grey Matter was climbing down Retaliator, the Omnitrix symbol wasn't on his back for a few seconds.
- Gwen used a locator spell to track Ben when he was lost, however in Ben 10 Returns (which takes place approximately 4-5 years later), Gwen states that this is the first time she has ever attempted a tracking spell.
- Instead of his Alien Force and Ultimate Alien voice, Azmuth had his Secret of the Omnitrix voice.
- The title of this movie is a nod to the video game "Destroy all Humans" and the Godzilla movie "Destroy All Monsters".
- In this movie, the color of ten-year-old Gwen's magical abilities are varying shades of glowing pink, magenta, and fuchsia just like eleven, fifteen, and sixteen-year-old Gwen's.
- In Australia, Cartoon Network hosted a competition for two kids to play a voice in the movie.
- In India, a lucky draw was held to select two children to watch the premiere of the movie in Malaysia. The lucky draw was called "Wassup alien?".
- Tara Strong and Meagan Smith returned to their roles as ten-year-old Ben and Gwen, respectively.
- In this movie, Gwen reveals that Ben's favorite shirt is also his only shirt.
- The ship Azmuth used to get to Earth was the same one he used to get off of Xenon during Ben 10: Secret of The Omnitrix.
- This movie was originally non-canon when the movie was first made but had been added to canon.
- Azmuth foreshadows Gwen's being educated about her powers being made possibly by mana, and when she asks what mana is, he simply responds that she will figure it out some day.
- Way Big is shown with his Alien Force/Ultimate Alien appearance instead of his original series appearance and his Omnitrix symbol is green instead of white.