The following is a list of episodes for Ben 10: Ultimate Alien
Season 1: 2010 (Episodes 1 - 20)
Image
Title
Number
Overall
Overall (franchise)
Original Airdate
Fame 1
1
99
April 23, 2010
Ben 's secret identity is revealed to the world , and an alien refugee is about to detonate a nuclear bomb.
Duped 2
2
100
April 30, 2010
Under pressure from his newfound fame, Ben comes up with a plan to be at more than one place at a time.
Hit 'Em Where They Live 3
3
101
May 7, 2010
Now that Ben's secret identity is out in the open, his old enemies team up to attack his family.
Video Games 4
4
102
May 14, 2010
Ben's celebrity lands him a starring role in his own video game.
Escape From Aggregor 5
5
103
May 21, 2010
Five aliens from another galaxy attempt to escape from their mysterious captor .
Too Hot to Handle 6
6
104
May 28, 2010
A radioactive alien menace tricks Kevin into freeing him from his containment suit .
Andreas' Fault 7
7
105
June 4, 2010
The team discovers that alien con-man Argit has somehow become the leader of the Forever Knights .
Fused 8
8
106
June 11, 2010
Ben is trapped in the form of his newest transformation , a form Aggregor intends to destroy.
Hero Time 9
9
107
June 18, 2010
A starstruck Ben dates a beautiful young movie actress , while his childhood hero makes a comeback.
Ultimate Aggregor 10
10
108
October 10, 2010
Aggregor's ultimate plan is revealed, and it's already too late to stop him!
Map of Infinity 1
11
109
October 10, 2010
Ben and his team travel to a bizarre half-frozen, half molten planet to prevent Aggregor from obtaining a priceless map .
Reflected Glory 2
12
110
October 15, 2010
JT and Cash get in over their heads when they take credit for Ben's heroic acts.
Deep 3
13
111
October 22, 2010
Ben, Kevin, and Gwen journey to the center of an all-water planet in an attempt to finally capture Aggregor.
Where the Magic Happens 4
14
112
October 29, 2010
Gwen takes the team to a dimension of magic , where their only hope of survival rests with her old foe Charmcaster .
Perplexahedron 5
15
113
November 5, 2010
Ben, Kevin and Gwen race Aggregor through a mysterious artificial planetoid designed to destroy anyone who enters.
The Forge of Creation 6
16
114
November 12, 2010
Professor Paradox holds the key to stopping Aggregor from tapping into the limitless power of Alien X .
...Nor Iron Bars a Cage 7
17
115
November 19, 2010
To settle an old score, Kevin voluntarily returns to the Null Void prison he once escaped.
The Enemy of My Enemy 8
18
116
December 3, 2010
Argit infiltrates the Plumbers' Academy with a plan to help the Vreedle Brothers do the last thing anyone would expect.
Absolute Power: Part 1 9
19
117
December 10, 2010
Ben is infuriated when Gwen asks Darkstar for his help defeating the team's deadliest, and most unlikely foe of all.
Absolute Power: Part 2 10
20
118
December 10, 2010
It's Ben and company's last stand against a foe they can't bring themselves to fight!
Season 2: 2011 (Episodes 21 - 32)
Image
Title
Number
Overall
Overall (franchise)
Original Airdate
The Transmogrification of Eunice 1
21
119
February 4, 2011
The team discovers a strange alien girl with no memory but Sunder has been hired to capture her!
Eye of the Beholder 2
22
120
February 11, 2011
Ship 's former owner, Baz-L , has been captured on the moon of a distant planet while stealing gems and Ben , Julie and the crew set out to save him.[CN 1] [revised ]
Viktor: The Spoils 3
23
121
February 18, 2011
The return of the evil Dr. Viktor !
The Big Story 4
24
122
March 4, 2011
When a mysterious meteor shower leaves behind an evil alien plant species , Ben 10 super-fan Jimmy steps up to save the day.
Girl Trouble 5
25
123
March 11, 2011
Gwen 's cousin, Sunny , pays a visit but she's more than meets the eye!
Revenge of the Swarm 6
26
124
March 18, 2011
When Julie is kidnapped, Ben blames Elena who swears she had nothing to do with it. But the Microchips in her lab point to the truth.
The Creature From Beyond 7
27
125
March 25, 2011
The Forever Knights accidentally unleash an evil force ! And at a Bellwood retirement home, a retired Forever Knight suddenly gets a very bad feeling.
Basic Training 8
28
126
April 1, 2011
Ben and the crew are forced to go through basic training at the Plumbers' Academy . And you can just imagine how well that goes.
It's Not Easy Being Gwen 9
29
127
April 8, 2011
You think it's easy being Gwen? Well you'll have second thoughts after you check out a typical day in the not-so-typical life of Gwen Tennyson.
Ben 10,000 Returns 10
30
128
April 15, 2011
Eon is back and it's up to an older and wiser Ben from the future to help the crew defeat him using the Hands of Armageddon to win the battle.
Moonstruck 11
31
129
April 22, 2011
Grandpa Max reveals the story of how he met Verdona and how he eventually was recruited to become a Plumber .
Prisoner Number 775 is Missing 12
32
130
April 29, 2011
When old George enters Area 51 and makes the entire base disappear, Ben and the crew learn that a mysterious Prisoner 775 may be behind it all.
Season 3: 2011 - 2012 (Episodes 33 - 52)
Image
Title
Number
Overall
Overall (franchise)
Original Airdate
The Purge 1
33
131
September 16, 2011
The Forever Knights factions have been united into one and an all-out war against the aliens on Earth erupts.
Simian Says 2
34
132
September 23, 2011
An evil Xenocite queen takes over the Arachnachimps ' home planet by attaching herself to a crime lord named Mizaru .[CN 2] [revised ]
Greetings From Techadon 3
35
133
September 30, 2011
A mysterious object crashes in the center of Bellwood, unleashing Techadon robots with one thing on their mind, destroying Ben !
The Flame Keepers' Circle 4
36
134
October 7, 2011
A fanatical group of whackos have taken to worshiping Vilgax of all people or aliens! And guess who has joined them, Julie !
Double or Nothing 5
37
135
October 14, 2011
Albedo , a.k.a. Negative Ben, returns as the star of a big stage production about Ben Tennyson's life. Sure, he needs the money, but what is he really up to?
The Perfect Girlfriend 6
38
136
October 21, 2011
When Ben finds himself in an intense battle against Ssserpent , Julie steps in and helps him defeat the slimy brute.
The Ultimate Sacrifice 7
39
137
October 28, 2011
Ben is suddenly NOT Ben and it's an all-out revolt as the aliens inside Ben's Ultimatrix demand their freedom.
The Widening Gyre 8
40
138
November 4, 2011
After a giant garbage-like creature appears and drags a boat down into the ocean, Ben and the crew investigate the Pacific Garbage Vortex.
The Mother of All Vreedles 9
41
139
November 18, 2011
Ma Vreedle returns to Earth with a cloning machine and a plan to unleash 300 billion Pretty Boy Vreedles on the planet.
A Knight to Remember 10
42
140
December 2, 2011
Vilgax gets a hold of Old George's sword , and tries to gain Dagon 's power. Big mistake! And Ben discovers a new alien hero: Eatle .[CN 3] [revised ]
Solitary Alignment 11
43
141
December 9, 2011
Azmuth reveals how old George first got the sword and defeated Dagon, and the crew travels to the Middle Ages to learn the truth.
Inspector #13 12
44
142
February 4, 2012
A mysterious Techadon Master visits Earth, looking for the Ultimatrix. And he turns out to be more dangerous than any Techadon ever imagined.
Enemy of My Frenemy 13
45
143
February 11, 2012
Gwen hopes to rescue Charmcaster . When she asks Hex to join her, he refuses saying he won't join a suicide mission.
Couples Retreat 14
46
144
February 18, 2012
After Darkstar opens the Door to Anywhere , Charmcaster comes through and the two team up to give Ben, Gwen and Kevin the fight of a lifetime.
Catch a Falling Star 15
47
144
February 25, 2012
Movie starlet Jennifer Nocturne springs the evil Captain Nemesis out of jail and the two escape and soon, Ben and Gwen are hot on their trail.
The Eggman Cometh 16
48
145
March 3, 2012
When vicious dragons invade Bellwood, it's up to Ben and an all-new alien named Juryrigg to battle the flying demons and return the peace.
Night of the Living Nightmare 17
49
147
March 10, 2012
Albedo is desperate to get his hands on the Ultimatrix and he goes to extreme measures to get it. Once he has invaded Ben's mind, all bets are off.
The Beginning of the End 18
50
148
March 17, 2012
As the final battle between the Forever Knights and Dagon's Esoterica heats up, Ben finds himself caught in the middle of an intergalactic showdown.
The Ultimate Enemy: Part 1 19
51
149
March 24, 2012
Dagon is getting closer and closer to entering our dimension thanks to an old foe.
The Ultimate Enemy: Part 2 20
52
150
March 31, 2012
Vilgax re-emerges in his most powerful form ever ! Can Ben stop him?
Crossovers
Image
Title
Original Airdate
Ben 10/Generator Rex: Heroes United November 25, 2011
When a mysterious rift appears over Manhattan, Rex is on the scene to see if there is trouble coming. However when Humungousaur comes from the clouds, Rex gets a bit more than he bargained for! Rex begins battling it out with the Vaxasaurian in Central Park, not realizing that Humungousaur is actually Ben Tennyson . Ben soon discovers he's in an alternate dimension and that he and Rex must team up to overcome their combined foes.
References 
This article is about the Ultimate Alien episodes in U.S. airing order. You might have been looking for the intended order or production order.
