The Beginning of the End

The Beginning of the End is the fiftieth episode of Ben 10: Ultimate Alien.

Plot
As Ben and Gwen are with Kevin in his garage as he finishes making his car submersible, they are attacked by the Esoterica, who are destroying anyone who stands in the way of Diagon's return. They fight off the Esoterica with Ben as Four Arms and Gwen is able to capture one of the members with her mana, as they can't teleport through mana. Kevin interrogates him and they are able to find out that the Flame Keepers' Circle is planning to let Diagon into this dimension.

The team go to the Flame Keepers' Circle headquarters and find out that none of the members are there. Ben transforms into Clockwork and uses his powers to show that they have all left to free Diagon. Meanwhile, Sir George is at the Area 51 fortress, rallying the Forever Knights to fight Diagon.

When Ben, Gwen and Kevin arrive at the location of The Seal with the Rust Bucket 3, they find the Forever Knights and the Flame Keepers' Circle at war, and neither side is winning. Ben asks them to land the Rust Bucket 3.

Ben tries to tell the Knights that he is here to help but the Knights refuse to listen and attack them. They force Ben and the team back into the Rust Bucket 3, and Ben transforms into Goop to fight them. After a difficult fight they are able to defeat them, and Gwen creates a mana shield at the door of the Rust Bucket 3, which was not closed, to prevent the other attacking Knights from coming in.

Gwen then senses Esoterica soldiers in the Rust Bucket 3, but still in between dimensions, watching the team without attacking. Ben convinces Gwen to that they must leave the Rust Bucket, and Gwen uses her shield to push the Forever Knights out of the way, as Ben, Kevin and her exit. Gwen uses her powers to point out where the Esoterica are entering this dimension, and Ben transforms into Fasttrack to knock them out before they can attack. Once that is finished, they proceed to the Seal, but realize that they cannot move through the many battles occurring to get there. Kevin has an idea, and tells Gwen and Ben to follow him. They fight their way through, reaching several high-tech catapults that the Forever Knights are using. Kevin uses one to launch Ben to the other side of the canyon and he transforms into Heatblast in midair, and proceeds to the Seal. Gwen then remarks in regret that she could have simply teleported him there.

Sir George, Winston and other Forever Knights are approaching the Seal. As they get close, Winston informs Sir George that he will protect him. While passing through the caves in which The Seal is set, they are attacked by Conduit Edwards, who fires an energy bolt at George while he isn't looking. Winston jumps in front of George and takes the blast for him. George turns around and attacks Edwards, who moves between dimensions for a while, firing at George before George is able to stab Ascalon through Edwards, killing him. George runs over to Winston, who tells him that it was an honor to be his squire, then dies. George says that Winston died not a squire, but a knight, and that his death will not be in vain. He runs forth to the Seal.

George reaches the Seal and hears Diagon's voice. Diagon claims that he will rule this dimension and take over it. The Seal cracks and Diagon lets out a minion of his, to destroy George. This turns out to be Vilgax, who has been fused with a Lucubra and reborn with Diagon's power. The other Forever Knights attack Vilgax, but he easily defeats them. At this moment, Heatblast bursts through the ceiling of the cave and lands inside.

Vilgax then moves forward towards the Seal and breaks it; though it remains intact and in place the cave wall around it crumbles and reveals Diagon's Dimension behind it.

Major Events

 * Winston and Conduit Edwards die.
 * Diagon's war begins.
 * Vilgax becomes the Herald of Diagon and he is merged with a Lucubra.
 * The seal to Diagon's Dimension is broken.

Characters

 * Ben Tennyson
 * Gwen Tennyson
 * Kevin Levin
 * Sir George
 * Winston (killed)

Neutral

 * The Forever Knights

Villains

 * Diagon (unseen)
 * Vilgax (merged with a Lucubra)
 * Flame Keepers' Circle
 * Conduit Edwards (killed)
 * Esoterica

Aliens Used

 * Four Arms
 * Clockwork
 * Goop
 * Fasttrack
 * Heatblast

Errors

 * When Four Arms sits, his underwear is red.
 * When Heatblast lands in the depression he created, he is shown to be sinking further and further i.e. in the first scene the hole is about his knee level, in the next it is at his waist and in the third it is almost at his chest.
 * When Clockwork showed the past in The Eggman Cometh, Gwen and her mom were talking backwards, but when Clockwork showed the past this time, Conduit Edwards was talking regularly.
 * When Goop was cut into half by the Forever Nights, even the Ultimatrix was cut.

Allusions

 * This episode shares its name with a Teenage Mutant Ninja Turtles episode.

Trivia

 * Clockwork's transformation sequence is shown for the first time.
 * This episode takes place two weeks after the events of Solitary Alignment.
 * It is possible the battle in the canyon is a reference to the Battle of Geonosis from the Star Wars: The Clone Wars movie as well as some of the other Star Wars battles.