Jesse bringing Romeo to Beacontown a few months after the 'incident' so Beacontowners won't hate him as much, and so Romeo can have some actual human interaction for once (he avoid Freds people like the plague) He speaks to Radar, who hadn't talked to him at all in those months and was stuck with the image of him being a murderous god that liked toying with people's feelings. To be fair, not too far off, he still has a sadism streak.
Radar basically just listens as Romeo rants on and on about the story of all the artifacts in the artifact room. He created the majority, while Fred and Xara made the rest. Radar is still afraid of him, and mad at him, but engages a little. Jesse is the most interested in the stories. Radar is mostly losing his mind at why he's there and still alive. And why Jesse is so casual with him.
The entire visit is Romeo infodumping on Radar because he doesn't have any other social skills and Radar having an internal crisis. Romeo keeps visiting until Radar interacts with him back, in which he's really happy about.