List of Ben 10: Alien Force episodes

After setting aside the Omnitrix some years ago, fifteen-year-old Ben Tennyson is enjoying a normal life. After winning a soccer game and meeting a girl named Julie, he visits Grandpa Max only to discover that he's disappeared. Inside Max's RV, the Rust-bucket, Ben finds a Holo-viewer with a recording from Max telling Ben that he has the Omnitrix and he's safe. However, Ben has had the Omnitrix ever since he took it off years ago.

He asks his favorite, fifteen-year-old cousin Gwen for advice, wondering if Grandpa wants him to wear the Omnitrix again. Soon, they meet Magister Labrid, an agent of the Plumbers. Stating that he's Max's partner in a case he was working on, Ben and Gwen decide to team up with him. Ben decides to put the Omnitrix back on. The first place they go is to a train station where an arms trade between the Forever Knights and the DNAliens, brokered by Kevin Levin. They attempt to arrest the Knights and the aliens, and a battle follows. When Ben tries to dial in his alien on his Omnitrix, the device reboots and recalibrates into a thin watch with a color scheme of green and black, making it more stylish and giving him access to 10 new aliens which are more powerful than his aliens he had before. The DNAliens get away, the Forever Knights escape with one of the weapons crates, and Kevin is captured. The Plumber asks Kevin for help in finding the Knights' hideout. Kevin, having not been paid (so he says), leads the group to a large castle. Inside, they find all sorts of medieval artifacts, but Ben accidentally knocks over a suit of armor which awakens a robotic dragon.

Fleeing from the dragon, the group runs into an army of Forever Knights. In the ensuing confrontation, Magister Labrid is killed when he saves Kevin's life, and Kevin joins Ben and Gwen on their search for Max to repay that debt. Using a leftover Laser Lance, Gwen is able to trace it back to its original owners. The soon find a secret underground base, they discover an army of DNAliens. Sneaking in, the find that Max isn't there anymore, and on their way out encounter the Highbreed in charge of the ship.

Annoyed at being discovered, the Highbreed commander defeats the team, and orders the termination of all life within a five-mile radius to eliminate any witnesses. Using Humongousaur, Ben is successful in his efforts to stop the commander, he learns that any damage he receives while transformed is inflicted upon his human form as well. Deciding to finish Max's last mission, Ben, Gwen, and Kevin become a team. But, according to another Highbreed deep inside another base, they have no idea what they're up against.

The authorities of a local town named Grover's Mill arrest a half-human, half-Pyronite boy named Alan for arson and criminal damage. Alan is wearing a Plumber's badge, which the local sheriff triggers when he confiscates it. The badge signals Kevin's badge, which leads Ben, Kevin and Gwen to Alan, thinking Alan's badge is Max's.

Elsewhere, Alan uses his pyrokinetic/thermokinetic abilities to escape the officers, and the resulting damage to a building leads the team to believe that Alan may have hurt Grandpa Max. After a battle with Alan, Ben discovers that the DNAliens are responsible for the damage, having built a huge, needle-like weather machine in the corn fields. With Alan's help, Ben destroys the machine, and afterwards Ben offers Alan to come with him, Gwen and Kevin. Alan decides to stay to clean up any DNAlien trouble that might still be in town, but offers to aid them whenever they need it.

Kevin meets with an old friend of his named Argit, who claims he knows the location of a particular piece of alien tech Kevin is looking for. Needing something to bargain with, Kevin steals Max's RV, the Rustbucket. Unfortunately, upon seeing the huge amount of Plumber's tech and weapons in the old RV, Argit double crosses Kevin, and steals the RV for himself, planning to pay off his old debts. With Ben automatically suspecting the worst in Kevin, the team follows Argit with a tracking device that Kevin hid on the Rustbucket's under carriage.

They find the RV, but it has been completely stripped for parts. Infuriated, Ben almost picks a fight with Kevin, but then Argit comes back. Using Echo Echo, the team is able to stop Argit. Still determined to get that piece of alien tech, Kevin storms away to seek out Vulkanus, having been told by Argit earlier he is in possession of the alien device. Kevin tries to make a deal with Vulkanus, but the later is still bitter over a double cross that Kevin pulled on him years ago. Vulkanus forces Kevin absorb a rare alien crystal called Taedenite, planning to use him as a living gem mine. He is rescued by Ben and Gwen and afterward, it is revealed that the item Kevin sought is a holo-viewer with another message from Grandpa Max, telling Ben that he will need to recruit a team of Plumber's kids.

Ben, Gwen, and Kevin set out on their mission to locate the other Plumber's children to recruit new members for their team. The first one they encounter is a young man named Michael Morningstar. Since Michael has all the Plumber's gear of his late father, as well as the fact that he seems to have been helping his city using his yellow-colored energy-controlling abilities, Ben and Gwen are quick to trust him. Kevin, however, remains suspicious (partly because of Gwen's romantic attraction to Michael). Seeing a reading on Michael's computers that there's a massive power draw at a local power plant, the team plus Michael decides to act. Finding a group of zombified school girls at the plant, the team engages in a short battle, and Michael "accidentally" lets them escape. Michael asks Gwen to dinner. Ben tries to stop him, but Kevin uses the opportunity to break into Michael's house to see if his suspicions are valid. As it turns out, Michael is making the zombies, draining the schoolgirls of their vital life-force energy and then commanding them to collect more strength for him. Fearing for Gwen's safety, they unfortunately arrive to help her too late. Michael drains Gwen's own magical abilities and becomes nearly unstoppable. With Ben and Kevin knocked out, Gwen saves the day by fighting back and comes to her senses by reabsorbing her abilities. Weakened and drained, Michael is then attacked by the school girls, leaving him withered and powerless.

Gwen's older brother, Ken, is missing and Gwen asks for Ben and Kevin's help to find him. In their search, the gang stumbles upon a Highbreed base in a small town called Santa Mira that manufactures Xenocytes: headcrab-like parasites that mutate humans into DNAliens. Ken has been infected by one of the Xenocytes, but Ben is able to remove it with the help of the voice-automated Omnitrix. With Ken in tow, the gang finds Grandpa Max inside the base. He explains that the Xenocyte eggs will be shipped across the country, and asks the gang to destroy them. While they comply, he sets about destroying the factory while searching for the egg-laying machine.

The team is at one of Julie's tennis matches. Gwen tells Ben to ask Julie to go on a date with him to a local boardwalk amusement park the Pier, and after an awkward attempt by Ben to ask her, Julie agrees, and they go. Elsewhere, out in the forest, a small dog-like Galvanic Mechomorph seeps out of a crashed spaceship. Seeking a plumber's badge signature, the Mechomorph soon finds Ben and starts taking control of the rides to get Ben's attention. After a few failed attempts, the alien than uses a ride to kidnap Julie.

Flying after the alien as Jetray, Ben tracks the alien to the ship. In the process, Julie finds out about the Omnitrix. Ben expects her to be freaked out, but Julie, however, finds Ben's secret very impressive, and even cool. The alien starts repeating the word "Ship", referring to the crashed space vessel. Deciding to call the alien Ship, Ben and Julie soon realize that what they though was a piece of the ships computer is in fact a bomb about to blow. Using Humungousaur to throw the bomb into space, they soon free the ship's wounded owner, Baz-El from the wreckage and help him fix his ship. Seeing how he has no use for Ship, Baz-El decides to leave Ship with Ben. It's dawn as Ben and Julie walk home. Ship chases a truck. Ben and Julie hold hands.

While Ben, Gwen, and Kevin are taking a break at Grandpa Max's favorite fishing spot, they see a mysterious cloaked woman leave a flower made of pure mana energy at the base of Max's favorite tree. When the team tries to meet her, she disappears. They decide to stake out the area for a while until the woman shows up again. The wait for three whole nights, and their patience is rewarded. The woman shows up, and is able to beat both Ben and Kevin in battle with ease. However, when she sees Gwen use her powers, she is amazed.

As it turns out, Gwen's magical powers are in fact inherited from the strange woman, who turns out to be Ben and Gwen's long-lost paternal grandmother, Verdona, who is an immensely powerful energy being called an Anodite from the planet Anodyne. After getting the full story from Gwen's parents, Verdona offers to take Gwen back to her home planet, Anodyne, where she can learn how to reach the full and maximum of all of her magical and life energy-controlling abilities (which would require seventy-five years). Gwen tells Verdona that she cannot leave her friends, not while the Earth is in such danger. Verdona then transforms into her true Anodite form, and decides to destroy Gwen's human body, thus releasing the inner Anodite within. After a short battle, Gwen firmly tells Verdona that she wants to stay on Earth and stay the way she is, saying that it's what Max would have wanted. Verdona accepts this and leaves, though she promises to check up on Gwen once in a while to see how she is doing.

The team faces off against a Techadon robot seemingly intent on destroying them. Using the new alien Goop, Ben is able to make the robot explode. Kevin grabs the severed hand of the robot (possibly planning to put its defense mechanisms in his car). Later, the team goes to Mr. Smoothie's for a break. Two bullies named Cash and JT, who used to pick on Ben when he was 10, decide to embarrass Ben by spilling smoothie on him. Ben, however, stands up to them, and makes a point to the other people at the smoothy shop pointing out how pathetic JT and Cash really are. Later that night, they see Kevin's car outside a restaurant, and decide to wreck it for retribution. They push it down a hill, smashing the trunk open. The grab the Techadon gauntlet before the car's alarm attracts Kevin. Back at their hang out, and abandoned mannequin factory, Cash puts the gauntlet on, planning on using its built-in laser blaster to destroy Ben once and for all and repair their reputation. Over time, the full robot armor begins to reform around Cash's body. Worried about his friend, JT goes to Ben's team for help. Kevin wants to go it alone as revenge for his car, but is soon defeated by the now immensely powered Cash. Seeking Ben out, a battle at Mr. Smoothie's rages between Ben as Chromastone and the almost fully restored Techadon. In the end, Cash is able to force the robot back into the gauntlet and restore control over his own body. Ben is able to overpower Cash as Chromastone, and JT manages to convince Cash to fight the Techadon's influence, reverting it back into the gauntlet. JT thanks Ben, and takes Cash back home, with Gwen and Ben forgetting about a beat up Kevin still being in the mannequin factory.

The team gets word of a strange creature roaming around an abandoned desert town named Los Soledad outside of Bellwood. The creature seems to be aging everything it touches at an accelerated rate. While Ben, Gwen, and Kevin investigate, see a strange man who seems to be able to disappear at will. After trying to fight him, the team soon formally meet the man known as Paradox, a scientist from the 1950s who was sucked into the event horizon of his time-travel experiment. Displaced from time and space, Paradox has existed for 100,000 years and is able to move through time at will. However, the same mistake that rendered him ageless created the creature they seek.

The Incursion Emperor Milleous's daughter Attea is kidnapped by a bounty hunter named SevenSeven (Brother of SixSix). Unless she is returned, Milleous plans to destroy the Earth. The Emperor's majordomo, Raff, seeks out Kevin to help on the search. Using Gwen's powers to track her, they teleport to a nearby dam to rescue her. In the assuring battle, the Dam is broken, flooding everything. Having no other choice, Ben uses the untested Alien X to try to fix the dam. The task proves simple thanks to Alien X's vastly strong reality-warping capabilities, but Attea is yet again captured by SevenSeven. Even worse, Ben finds himself locked in endless debate with the other two separate personalities, Bellicus and Serena, inside the alien, unable to move or transform back without their consent. When all of them are teleported onto Milleous' ship, Kevin and Gwen have to protect Ben while trying to save the Earth from the double-crossing Attea who has used Sevenseven to help take over her father's empire. Seeing that Gwen and Kevin have been captured, and that the Earth is only seconds away from being destroyed, Ben finally grows tired of the fruitless debate and demands to be transformed into another alien which can actually get the job done. He manages to save the Earth as Swampfire, but resolves never to use Alien X again as its godly, omnipotent abilities are not worth the price.

After a Plumber setup to find out if the team has been masquerading as Plumbers, Ben, Gwen and Kevin are forbidden to fight against the Highbreed threat by Plumbers Magister Prior Ghilhil. Ghilhil has doubts the Highbreed are even as much of a threat as they claim. Elsewhere, a mysterious powerful new enemy 'employs' a Highbreed to attack the team. Having also tipped off Ghilhil, all three side are captured by the team's old enemy, Michael Morningstar.

Paradox and Azmuth arrive on Earth to warn Ben of the approaching Highbreed fleet. Gwen and Kevin gather all the allies they've met (Alan, Cooper, Julie and Ship, as well as their enemy Darkstar) to counter the threat. Meanwhile, Azmuth reveals to Ben that the Omnitrix contains the DNA of every sentient species in the galaxy, over one million in total, and unlocks the Master Control so Ben can effectively combat the Highbreed.

This includes all of his old aliens. With Ben as Cannonbolt, the team converge on the Highbreed hyperspace jump gate in Los Soledad in an effort to prevent its activation, but the attack only provokes the Highbreed in charge to summon the fleet ahead of schedule. To try and stop the fleet coming through, the team with Ben as Upchuck attempts to destroy the hyperspace jump gate but it does not work. Ben then turns into Way Big, and tries to rip down the gateway, it starts to work but as the Highbreed in charge now preemptively activates the gate, it initiates and knocks Ben unconscious.

The team has to get to the captain of the fleet, on the Highbreed head ship to stop the invasion. Ben, Gwen and Kevin quickly head to the captain of the fleet. The Highbreed commander and the team fight, and an enraged Gwen unleashes her dormant Anodite form for the first time in a desperate attempt to save Kevin, but returns to her normal human form. The trio is then surrounded by a group of DNAliens, but are saved by Grandpa Max, Pierce, Helen and Manny plus one Null Guardian, who have regained control over the Null Void.

Ben, Gwen, Kevin, Azmuth and Ship as a spaceship head to the Highbreed's home world to confront the Highbreed Supreme with Ben as Brainstorm being the pilot. The Highbreed Supreme refuses to recall the fleet, and Azmuth reveals that the Highbreed's obsession with genetic purity has resulted in sterility in their species: they intend to cleanse the galaxy of all life in retaliation. Using the Omnitrix, Ben sends out an energy wave that reprograms the DNA of every Highbreed in the galaxy, fusing their DNA with random species from the Omnitrix to repair their genetic damage. Stunned and horrified at the loss of the genetic unity, the Highbreed Supreme immediately consider racial suicide as their only honorable option, but Reinrassic III, who has returned, convinces his race that their new impurity is desirable, and the fleet is recalled. Max decides to take in Ben's recruits (all except Darkstar, who ran off) and train them. As a side effect of reprogramming the Highbreed genetic damage, Ben finds the Master Control has been reset, leaving him with brand new aliens as well as his old ones.

Ben squares off against Vilgax.

The Omnitrix malfunctions, turning Ben into a ruthless and aggressive alien while on an intergalactic peace mission.

The Plumbers' Helpers travel to a Plumber station to rescue Max from an insane, rampaging Ben.

Vilgax and Albedo return and team up to kidnap Kevin and Gwen so that they can take down their sole strongest enemy, Ben Tennyson.

Ben gives up the Omnitrix and overcomes seemingly impossible odds to defeat Vilgax, who has betrayed Albedo.