Multiverse at Stake!

"Multiverse at Stake!" is the 1st episode of Worlds Collide.

Official Synopsis
Bowser Jr is confused on why Bowser had a prism in his possession secretly and wanted to find out why, meanwhile Steven is concerned about his friends being poofed and trapped on a planet far out of his reach. Now the two get teleported to the planet – Kepler 22-b and have to work together to stop Bowser, save the gems and the Multiverse.

Plot
The episode starts with Bowser Jr playing video games with an unnamed Dry Bones in his bedroom waiting for his dad, Bowser, to return with the pizza he supposedly ordered. As he leaves the room, he sees Bowser hiding something as he walks by, Junior questions it but Bowser tells him to leave him alone. Junior returns to his room and tells Dry Bones about what he saw, he was obviously fascinated by it and wanted to know more about it. Junior then brushes it off and they continue to play video games. Shortly after, Junior's controller dies and leaves his room to find something to eat, he sees Bowser again, acting even more suspicious and complaining that the object won't listen to him. Junior confronts him again and Bowser tells him once again to leave, this time more angrily.

Junior returns to his room a third time, whining about how hungry him and his friend are. Dry Bones tells him he should probably give Bowser some privacy, but Junior calls him a nerd for simply having common sense. He then tells Bones about his plan, he is going to sneak up on Bowser and watch him handle the object, Bones agrees and tell him to do it. As Junior hides and sneaks on his father, he overhears him and Kamek conversating about the object. Bowser tells Kamek that the object is the Light Prism and how he got it from Steven's universe. He hears that with the Prism in his possession, he can take over the universe and even them multiverse with it. Kamek cheers on him and claims he can finally show the Mario brothers who's boss once the multiverse is his and that he is worthy. Junior then leaves with excitement, and heads back to his room to tell Dry Bones about what he heard.

Junior tells his friend how amazing the prism was and where his dad got it from. Dry Bones claims that Jr should ask his dad to give it to him, Junior agrees as him and his siblings haven't been trusted properly in a long time, he storms out of his room in pride, he confronts his father again and tell him he knows what he has. Bowser asks him what he was doing and Junior owns up, saying he spied on him and Kamek. Bowser feels utter regret thinking he could trust his son to leave him be, so that's when he puts his foot down and tries to activate the Prism elsewhere. Junior questions where he's going in fear, Bowser blatantly ignores his question and opens a portal using the Prism. Bowser says he's sorry and he has to be left alone as he jumps into the portal, leaving Jr and Dry Bones behind. Junior picks himself up with pride as says he going into the portal, Dry Bones tells him not to as it could lead to extreme danger. Junior apologies and says he not going to get left behind again, he jumps into the portal just as it closes.

Junior is then warped to a mysterious jungle on another planet, way beyond his universe.