The Secret Saturdays come to Bellwood to help Ben and Rook investigate a rash of chupacabra attacks where they've been draining alien lifeforce.

Ben as Gravattack attempts to moderate a fragile peace treaty, but must endure the attacks of tiny alien fleas, which have inhabited his body. Rook shrinks down in attempt to get the fleas off him before the peace treaty is ruined. But it turns out that the Lewodon named Poltroon, sent the fleas onto Gravattack to destroy his core, causing a meltdown in attempt to destroy both the Lewodons and the Appoplexians, therefore causing a war between the 2 species and taking power to destroy his enemies. Now Rook must find a way to change Ben back before they are destroyed and to stop Poltroon.

Octagon and Rhomboid Vreedle kidnap Pretty Boy Vreedle, but when Ma Vreedle finds out he's stolen, but not by whom, she threatens to blow up the sun if Ben and the Plumbers don't find her missing son! Meanwhile Ben tries to hide from his mom so he won't get seconds on the dinner that he hates.

Dr. Joseph Chadwick is back as a Forever King. He is now leading the remnants of the Forever Knights who threaten to erase all alien DNA on Earth as Ben and Rook work to stop the Forever Knights. Jimmy discovers that Will Harangue is somehow involved in Joseph's plot.

Ben, Gwen and Cousin Lucy try to find out how Psyphon's thugs are getting Plumber technology. Gwen suspects that Lucy is the mole because of all her shape-shifting abilities, and her love of tricks when she was younger.

Albedo, disguised as Ben, seeks a device that will finally change him back into his Galvan form. Meanwhile, the real Ben is locked in Albedo's prison cell at Plumber HQ.

After Ben falls for Albedo's trap, Grandpa Max and Rook search all over the galaxy looking for Ben. Meanwhile he's secretly trapped on Khyber's hidden personal hunting preserve fighting Khyber's new pet that now wears the Nemetrix.

Ben, Rook and Grandpa Max must stop Ultimate Albedo from absorbing all of Azmuth's profound knowledge and taking over the galaxy. Gwen and Kevin show up just in time to help with their struggle.

Ben, Rook, and Grandpa Max have their hands full when Phil returns as a half-human, half-Terroranchula creature and starts absorbing all of the electricity and lightning in Bellwood. Phil seeks Max's help to tame the monster within.