Cuphead & Mugman are celebrating their victory with Ice Cream. They notice a storm is coming & took shelter in the cave where they had discovered a strange artifact in the cave. As the storm clear,The Brothers left the cave,but not before Cuphead took the artifact. At home,Mugman discovers this and the two fight over the artifact before it fell & shattered,creating a massive shockwave.
That morning,Cuphead & Mugman goes to the town where they see people are running in panic from Brutus. After Mugman gets overpowered,Cuphead fights with him until they're interrupted by the Covenants,led by Truth. They saved by Dante,who explains that he sense a shockwave caused this,pulling everyone from their worlds & reveals that Artifact is a dimensional tablet. Cuphead,Mugman,Dante,& Brutus searches for the pieces of the tablet that has been shattered. Dante & Brutus are confronted by Marcus Fennix. They are also confronted by Altair. As they each battle,one of the pieces gets taken a Robotic version of RAAM,who was believed to be killed.
& Mugman are confronted Conker the Squirrel,who threatens them with a gun. His girlfriend,Berri stops him. The Panther King appears & took the piece. The Professor Von Kriplespac & Don Weaso are surprised to see Berri & Panther King,saying they're dead,much to Cuphead,Mugman,Conker,& Berri's confusion. They are both saved by Banjo & Kazooie. Kriplespac explains that he put an alien egg in the Panther King's milk & Weaso had killed Berri. Truth appears & suggests to form an alliance.
Dante explains to Conker & Berri about this possibility about her death. Marcus searches for the pieces when Frank West appears and tried to hit him with a bat,believing that he's a psycho. The two fought eachother until the Covenants appears along with RAAM. They are both confronted by Truth,who reveals that he found RAAM's corpse & enhanced him as a part robot. They are saved by Master Chief,Shepard,Claptrap, & Ryu Hayabusa. The heroes decide to work together.
They went to the covenant base when they battle against them. RAAM,Kriplespac,& Weaso escapes while Berri kills the Panther King. The Heroes retrieve the pieces,but Truth tried to intervene. Cuphead jumped onto Truth and damaged his chair. As Truth grabbed him by the handle,Master Chief shoots him in the head,killing him. After the pieces are put back together,the Heroes bid farewell to eachother.
On the way home,Mugman asks Cuphead about what happens next,which Cuphead answers that he wasn't sure,but they have nothing to worry about.