Team Tennyson stops in at a fringe family reunion, and Ben encounters a whole lot more than kooky cousins— namely, Kevin 11 and the Bugg Brothers, whose latest crackpot invention sparks a series of hilarious head-swaps between all parties.
The episode starts off with the Tennysons arriving at their family reunion. Max tells Ben and Gwen to stay on their best behavior, and not to have a repeat of last year. Ben walks in with the deviled eggs Max cooked. One of the family members states that they're watching Ben. Aunt Kathy comes up to Ben telling him that she strongly opposed to inviting his family back this year. She then hugs Ben, and asks him how he's doing. Max states that it really brings back memories. Ben questions if he knows all of these people. Another family member, Alfred, walks up to them. Max and him shares some laughs. Max tells Ben that Alfred Lord Tennyson is his second cousin. Elsewhere, Grandma Rita shows Gwen pictures of Max in his youth. Ben begins to laugh. Grandma Rita leaves to find more photos of Max. Max states that the kids are doing great. Ben leaves to go get some deviled eggs, but he notices Kevin, who is eating food. Ben confronts him, telling him that those eggs don't belong to him. They prepare to fight, but Gwen tells him to bring the fight elsewhere, away from the reunion. Ben transforms into Four Arms, and Kevin transforms into Crystalfist. Aunt Kathy hears a noise, and Max distracts her. He then tells Gwen to go see what's going on. Four Arms manages to out match Crystalfist, and sends him flying into the sky. He takes a tree, and hits him across the park.
Ben times out, and leaves to go hide somewhere. He jumps into a dumpster. There he sees the Bugg brothers. Ben questions what they're doing there. Maurice states that they're there to test out his latest invention. Maurice demands Sydney to hand him something. Maurice introduces Ben to the particle decimater. Maurice explains that it is a shrinking ray. While he talks, ben transforms into Heatblast. Maurice hits Ben with the device, however, turns out, it's a head switcher. Heatblast finds his head on Maurice's body, and Maurice's head on the former's body. Maurice is confused, as it was not the shrinking ray. Kevin returns, still Crystalfist, and insults Ben for his head being swapped. Kevin's head is then sapped with Sydney's. Maurice demands Kevin to hand it over. Kevin questions who he is, and why he made a head-swapper. Maurice explains that it's one of his earliest inventions, and that he was going to unveil his latest creation, until Sydney brought the wrong device. Sydney and Maurice surrounds Kevin.
Heatblast wakes up, and notices Kevin. He attempts to use his powers, but he realizes his body is still swapped. Sydney and Maurice tackles Crystalfist, and the helmet flies into the air. Heatblast runs towards it, and attempts to catch it. Heatblast gets hit by Sydney. Gwen arrives, and Heatblast tells her to get the Helmet. She shoots the helmet, but Sydney deflects it, making it hit Max. Gwen and Max's heads switch. Crystalfist and Heatblast both times out. Ben grabs the helmet. Kevin takes it, and switches heads with Maurice. Kevin's head is now on Ben's body, and Maurice's head is now on Sydney's body (which was his original body prior to the series). Kevin picks up the helmet, as an attempt to switch his head back. Maurice takes it from Kevin, and uses it to switch his head back. Maurice is back to his bug-like body, however, a squirrel has the device, and causes it to malfunction. The helmet begins shooting everyone. Switching everyone's heads randomly. Eventually, Sydney's head is back to normal, as well as Maurice. Kevin threatens Sydney, holding Maurice in his hands. He questions how he gets back to normal. However, Kevin couldn't understand him. They then begin to argue. Ben, in Kevin's body, from behind a tree, hopes for them to take each other out. He then gets a call. The call is from Forever Knight, telling Kevin to report back. Ben pretends to be Kevin, and tells him that he is hanging around with family. Forever Knight scoffs, stating that he has no family, and without him, he has no one. Ben figures that it might've been the reason Kevin came to the reunion. He just wanted to be around family.
Kevin insults the Bugg Brothers, on how their plan was so dumb. Ben yells out, telling Kevin to switch them back. Maurice asks for the helmet back, however Ben transforms into Rath and destroys it. Rath threatens them with his sharp claws, but Maurice and Sydney runs away. Rath looks around for Kevin. However, Kevin, from behind a tree walks away. Gwen walks up to Ben asking what happened to the helmet, since Max is stuck in a squirrel's body still. Rath looks down at the destroyed pieces.
Aunt Kathy says her goodbyes to the Tennysons. Max tells Gwen to plug in the address for Phil's house, since he can fix this. Max checks if everything is okay with his body. Ben gives tells him that the squirrel on Max's body likes the deviled eggs, so he won't get out of control.
Kevin interacts with the Bugg Brothers for the first time.
Grandma Rita: Whoo! And here is your grandpa Max siting on Santa's lap. (Shows another picture). Gwen: Ah! Grandma Rita: Yeah, that handsome baby grew into the most awkward-looking teen I'd ever seen! Max: Oh, what's Grandma Rita -- Oh! Oh! I thought those were destroyed! Ben: (Laughs). Gwen: Have you always worn Hawaiian shirts? Max: What? The material really breathes!
Gwen: Well, so far, so good. Right Grandpa? Max: You kids are doing great. Ben: See? It's all good. Now to get some of them deviled eggs...(Groans). What is he doing here? Gwen: You don't think he's related to us, do ya? Max: Now, Ben, don't do anything rash. Ben: What? I'm just gonna say hello. Kevin, that egg doesn't belong to you. Kevin: Come and get it. Ben: I think you should leave. Kevin: You really want to do this here? Ben: You bet I do! Gwen: Ben! Ix-nay with the ouble-tray. Perhaps you'd like to show your friend Kev the big empty park over there. Ben: Okay! Come on Kev. Let's go see the park.
Maurice: Allow me to introduce you to... the particle decimater! Ben: Kind of looks like a bonnet. Maurice: A bonnet? Please! This, my feeble friend, is a shrinking ray. With this, I'll destabilize the national economy, undermine the government, disrupt social order, and wreak havoc upon everyone in the world. Countries will bow before me. No more waiting in likes for coffee!
Maurice: Drop the helmet! Crystalfist: Helmet? It looks like a bonnet. Maurice: It's a cranial displacer! Crystalfist: (Blinks confused). Maurice: A head-swapper, and I would like to have it back. Crystalfist: Who are you, and why would you make a head-swapper? Maurice: I am Maurice, and that is one of my earliest experiments. I was going to unveil my latest creation, but Sid over here brought the wrong device. Crystalfist: Who's Sid? Sydney: (Grumbling). Crystalfist: Hey, his head is on my body.
Kevin: Cool it, cockroach. I suggest you keep those arms nice and high. Now, how do I get myself back to normal? Sydney: (Squeaking). Kevin: What? Maurice: Don't listen to him. Sydney: (Squeaking). Maurice: You're the one that got us into this mess! Ben: Boy, nothing would make me happier than to see those loser take each other out. (Phone rings). Huh? Forever Knight: Kevin, where are you? We have work to do. Ben: Uh, hey, jerk-face. I'm, uh, just hanging with my family. Whatevs! Forever Knight: Family? (Scoffs) That's a laugh. You have no one. Without me, you're all alone, remember? Now, stop playing around and report back here at once. Ben: No family? Could that be the reason he crashed my reunion? he just wanted to be around family?
Kevin: So your plan to destabilize the world was to shrink stuff? Are you both brainless? Sydney: (Squeaking). Maurice: (Laughs). You tell him, Sid! Ben: Kevin! If you want your body back, you just have to blast me with the... Kevin: Okay!
This episode chronologically takes place before Roundabout as Kevin is not yet trapped between space and time.[DR 1] This is because new episodes were ordered at the last minute.[DR 2] The extra season 3 episodes were supposed to be spread throughout the season.[DR 3]