Rose, Captain Jack, and the Doctor -- and elsewhere, Nancy -- narrowly escape the attack of the gas mask zombies after the Doctor is very heartbreakingly/bad-assly stern with them. Jack admits that the space junk is just junk, and the Doctor gets very shirty. Everybody runs around Albion Hospital for a million years -- in classic Who style -- but the Doctor and the Captain find the time to get manly-ridiculous with each other in a million ways (including: banana size, screwdriver size, and sonic blaster size), while Nancy outs black-marketer/down-low enthusiast Mr. Lloyd. Two simultaneous scenes combining thereby to make this the gayest episode of any show ever which does not include the word "queer" in the title. But also, the not-gayest episode ever of this show, as Rose and the Doctor involve themselves in a particularly hairy game of "I don't like you in that way...or maybe I do." Turns out that the Doctor's done his share of "dancing," and not just with Grace Holloway. It is discovered that Jack was once a Time Agent, but had two years of his life Men In Black-ed right out of his brain. Also that he likes boys plus girls plus whatever. Nancy gets locked up next to a soldier who's undergoing the Change of Gas Mask, but is saved at the last moment by the Doctor. It's finally discovered that the actual space junk at Limehouse Green has been spouting nanogenes since Jack parked it, which focused on little blown-up Jamie in his gas mask, and attempted to repair him -- thus resulting in the gas mask disease that's sweeping London and making Captain Jack personally responsible. Luckily -- as the bomb drops and the zombies approach -- the Doctor figures out that Jamie and the suspiciously young-looking Nancy have a "Sister! Mother! Sister! Mother!" conundrum on their hands, and pushes her to reconcile with her son. Thus giving the nanogenes a descriptor of what real, parental human DNA looks like. There is an explosion of awesomeness, as everyone who succumbed, including good old Dr. Constantine, are repaired and then some -- healed of things like amputated limbs. Grace everywhere. Sniff...but that's not all! Jack sacrifices himself to get the bomb out of the sky and into space, and at the last second the Doctor and Rose TARDIS into his ship, save his hot self, and make him the newest Companion! In case you're not feeling the slap of pure joy across your face, let's reiterate: Just this once, grace is built from freedom and love, instead of horror and blood and pain like usual. Just this once, nobody dies. Just this once: the Doctor dances.