Ben and rex team up to stop alpha from absorbing other EVOs but fails where ben got an awesome yet effective idea to launch rex to alpha's heart where he can take the core from it. Ben reveals that alpha was actually sent into the Null Void which is a prison dimension for criminals. Caesar sent it to another dimension but it came back with the rift. On their chase, caesar the brother of rex comes to them and tells them about the creature named Alpha which was a mean of creating nanites. Ben ultimately escapes the containment by turning himself into big chill, rex goes after ben. Ben has been locked in a containment unit where he is shocked that no one knows him even being a celebrity. The creature self destructs, leaving rex angered on ben. Ben also tries to stop the EVO but didn't know that it can be cured by rex. With ben, something else also comes out of the rift, with bobo and six after it. Rex finds himself fighting with Ben who has changed himself into humungousaur. Doctor Holiday scans the rift and tell them that something is coming out from the rift.
Providence trying to stop the rift but they fail so they call Rex, Agent Six and bobo. Episode plots a mysterious rift which begins in Manhattan. Ben 10 / Generator Rex Heroes United is an animated episode.
