The Return of Dagon Arc

The Creature From Beyond is Liberated
Underground, the Forever Knights accidentally break the seal that was imprisoning to a legendary and dangerous creature of another dimension. The dangerous creature gets hold of the minds of everyone present, turning them into his slaves. Meanwhile at the same time as the creature is liberated, in Bellwood's convalescent home one of his tenants reacts and leaves, the elder is called by the nurse as " Old George ".

Another faction of the Forever Knights is going to investigate the site of the events, but in the place Ben, Gwen and Kevin appear, both decrees remind a truce to look for the creature and for the missing gentlemen. After crossing the streets in search of the creature they find her in an alley possessing a policeman who attacks them. The Creature also possesses Gwen and Winston (the young squire), but it does not manage to possess Kevin since he was in his form of metal, Gwen manages to return in if, whereas Winston is kidnapped by the Creature.

The Destruction of the Area 51
At the Area 51 base, Old George appears and defeats all of the security guards. Seconds later, Area 51 disappears.

During a campfire that Ben started using Swampfire, Max is having a phone call with Cooper about the disappearance of Area 51. He them tells Max that Colonel Rozum won't say much. Max tells Cooper he's on his way only to find out that Ben, Gwen, and Kevin had been eavesdropping.

The group arrives at the site to see what had happened. Ben decides to go have a look inside after finding out that Area 51 was a holding facility for aliens. Afterwards, Ben describes the conditions as "inhuman" with Rozem replying that "they're not human". Ben demands that Rozem releases all 774 aliens but Rozen responds that one of the prisoners is missing. The prisoner escapes into the Plumber Ship Cooper used and Ben chases it as Rath. After a short battle against a "missing alien prisoner", a "stolen Plumber Ship", and gravity, Rath does cause the ship to crash, and the prisoner's location was able to be determined.

When the team arrives, they fail to override the ship's self destruct sequence but they manage to find the alien terrorizing a small town. The group manages to take him down and they explain that the Plumbers will listen to his story of how he lost the war on his home planet and how he lost his family as well. He instead decides to go after Rozem. Gwen unknowingly release the prisoner from her shield. The group then returns to Max in order to gain clearance into Rozum's neighborhood. The group gets to the Prisoner before he can actually kill Rozum. Because he was too strong for Wildmutt, Ben decides to go Ultimate Wildmutt. After defeating him, the prisoner begs Ben to finish him off so that he can be with his lost family.

After being taken in by the Plumbers, Ben scans the alien's DNA and unlocks ChamAlien (which Ben jokingly calls "overkill" because of the episode's earlier scene. The episode ends with a strain in Max's and Rozum's friendship.