Kabuto fights the new worm (Bellcricetus Worm) in Masked Form, driving it off with the Kunai Gun. Kagami is still looking for Ryou, having flashbacks of a burning baseball & glove, but he doesn't find him.
The next morning, Kagami goes to the Bistro, where Hiyori is grouchy at him as usual (she doesn't do much else in this episode besides get mad at Kagami.) There's a little sideplot about several boxes full of fish adressed to his name, although this is actually Tendo's doing. Kagami gets a chance to meet Tendo's sister, who arrives and like her brother quotes their Grannie.
The two of them (with Kagami lugging the boxes) go to Tendo's house, where he prepares breakfast for everybody. Tendo's sister asks Kagami about what's been going on lately with her brother (i.e. Kabuto) but he's reluctant to answer. We also find out that Kagami himself has/had a younger brother, and that Tendo really is that good of a cook. But I still bet Shouichi could take him! In the funniest moment of the episode, Kagami suddenly stands up and screams "I HAVE WORK!" (lit: Part-time job) and runs out, but not before promising Tendo's sister to come back some time.
Through a flashback, we see that the younger brother Kagami mentioned was that Ryou guy, and the burning stuff scenes are actually not from the Meteorite crash, but a seperate time when Ryou (a pitcher) burned his baseball equipment.
Tendo heads to the Bistro, and on the way is watched by Bellcricetus & the Worms.
While waiting for a train to pass, Kagami ends up running into Ryou!
Tendo arrives and helps Hiyori clean dishes (of his own voilition) and asks her about Kagami's little brother. She states that she heard he vanished about 2 years ago. Prior to this he had a conversation with Kagami in the park, where the latter mentions the Worm, although Ryou is unfamiliar with that name. Back in the present, Kagami arrives, announcing there will be a party tomorrow, as he's just reunited with his long-lost little brother! Tendo, of course, is already suspicious.
Misaki later runs into Tendo, who cryptically mentions Kagami's brother before driving off. She's still pretty upset about him stealing the Kabuto Extender, I think.
Kagami later meets with Misaki & Tadokoro, who break the bad news: Ryou is probably a Worm. Kagami doesn't want to believe it, but knows deep down its the truth. It is suspicious that he suddenly appears again now, and Kagami vows to be the one to destroy him and avenge his real brother.
Kagami confronts Tendo, upset that he brought up his brother to Misaki (I think), and a little scuffle ensues where they both punch each other (although naturally Tendo has the stronger punch.) Kagami wants to be the one to destroy Ryou, although Tendo doesn't seem convinced he can do it and believes it's his job. After some more arguing, Kagami leaves and is followed by a man in black (ZECT agent.)
Kagami meets Ryou at a baseball field, Ryou mentioning his promise (from one of the flashbacks) to someday meet him again. The Zectroopers soon arrive, and Kagami, despite knowing better, instictively tries to shield Ryou, who becomes Bellcricetus Worm. Other Worms arrive and help trash the toops, who I'm now convinced are either personally trained by Faiz's Mihara, or are clones of Hibiki's Sabaki. Bellcricetus Worm turns back into Ryou and explains that when a Worm steals a person's form, they also take their memories, which is why he knew about everything Kagami remembered. He even has the old baseball (saved from the fire, I think) they were going to play catch with. Throughout this whole sequence, Kagami has been finding it impossible to shoot Ryou/Bellcricetus Worm with that little gun thingy he had last episode. This is partly because Ryou/Bellcricetus Worm told him that since he now has both his brother's mind as well as form, destroying him would be the same as destroying the real Ryou. Tendo arrives, quoting his grandma once again, and transforms dramatically as thunder crashes and it begins to rain.
Kabuto Masked Form easily defeats the other Worms, but Bellcricetus Worm proves to be much tougher. However, Kagami soon notices that Kabuto isn't bothering to fight back. He just keeps getting knocked down only to stand up again. Kabuto tells him that he (Kagami) wanted to be the one to kill Ryou, but Kagami realizes he can't bring himself to do it/isn't strong enough, so he begs Kabuto (he calls Tendo "Kabuto" this time) to do it for him. Cast Off, & Clock Up.
The rain freezes in midair, and there's a cool-looking fight with Kabuto & Bellcricetus Worm knocking each other around through the water droplets. Kabuto finishes things off with a Rider Kick, and time goes back to normal just as Bellcricetus Worm is about to explode. He drops the baseball, and the image of Ryou begins to emerge from him (this happened earlier, whenever Bellcricetus Worm talks) before he goes boom. Kagami drops to his knees, and Tendo tosses him the baseball before walking off, leaving him to mourn what is basically the second loss of his brother.
As he walks through a tunnel, someone in a raincoat watches Tendo.