Meanwhile, the gifts brought by the Adherents of the Repeated Meme, small metallic spheres, are revealed to be robotic spiders that immediately work at disabling functions on Platform One. The Steward of Platform One recognizes something is wrong, but is killed when the spiders cause the solar filter of his room to lower, exposing him directly to the powerful solar radiation. The Doctor goes to investigate with the help of Jabe, a humanoid plant being from the Forest of Cheem, and discover the Steward's death and the spiders. Rose attempts to learn more from Lady Cassandra but only gets more upset over Cassandra's arrogance, and walks away, only to be knocked out by members of the Meme. She wakes up in an observation room, the solar shield slowly lowering, and calls for the Doctor to save her. The Doctor finds he can stop and raise the shield, but cannot unlock the observation room, and so turns to the various guests.
The Doctor uses a spider that he captured to determine that while the Meme released them, they are only empty shells, and that the real controller is Lady Cassandra. Cassandra admits to this, and was planning to use the situation as a hostage crisis to get money to pay for her repeated operations, but now will simply let the assembled guests die, then profit from the stock increases of their competitors when they are dead. Cassandra transmats to her ship as the spiders bring down the shielding and the gravity satellites are turned off ; The direct radiation causes the solar filters to strain and crack, killing several of the guests from the intense radiation exposure, and leaving Rose to scurry to find some shelter within the observation room. The Doctor and Jabe travel to the bowels of Platform One where the system to restore the automated shields is located, though it requires one of them to travel through several spinning fans. Jabe recognizes the Doctor as the last Time Lord after a great war, and sacrifices herself to hold down a switch to stop the fan blades, allowing the Doctor to reactivate the system just before the expanding Sun hits the station and destroys Earth.
The Doctor returns to the remaining guests and Rose, free of the observation room, and uses a device to transmat Cassandra back onto the station. In the elevated temperature and without moisturizing, Cassandra begins to dry out and crack, and while she begs for mercy from the Doctor, he refuses to listen, and shortly, Cassandra explodes. Rose notes that with all the events that occurred, no one had witnessed the actual destruction of Earth. Returning to Rose's present, the Doctor explains to her that his own planet was burned alive and that he is the last Time Lord, and that people tend to forget that things don't last forever. Rose sympathizes with the Doctor as they enjoy some chips on a sunny London afternoon.
The concept of a Doctor-supercharged communications device first appeared in The Three Doctors (1972–73), where the Second Doctor modifies the Brigadier's radio telephone to allow him to contact his men through interference generated by antimatter. The Doctor also gives the Brigadier a "space-time telegraph" which he uses to summon the Doctor to assist with the events of Terror of the Zygons (1975). In the "unofficial" animated webcast Scream of the Shalka (2003), the Doctor uses a mobile phone that is part of the TARDIS to communicate with the outside world even while falling into a black hole.
This is the fourth time in the series that Earth has been burned by the Sun, the other occasions being sometime after the 30th century in The Ark in Space (1975), two million years from the present in The Mysterious Planet (1986) and ten million years from the present in The Ark (1966).
The other guests attending Platform One, as announced by the Steward, include the brothers Hop Pyleen, inventors and copyright holders of hyposlip travel systems from the exalted clifftops of Rex Vox Jax; the cybernetic hyperstar Cal "Sparkplug" MacNannovich (plus guest); the avian Mr and Mrs Pakoo; the chosen scholars of Class Fifty-five of the University of Rago Rago Five Six Rago; and the Ambassadors from the City State of Binding Light (oxygen levels must be monitored strictly at all times in the Ambassadors' presence). The Steward informs the Doctor that teleportation is banned under "Peace Treaty 5.4/Cup/15" (presumably the name of the treaty followed by the year it was enacted). How exactly this dating system works is never explained.
In conversation with the Face of Boe, the Moxx of Balhoon mentions the "Bad Wolf scenario." On the BBC's Bad Wolf website, it was listed as "the classic bad wolf scenario". (The subtitles of the DVD release give the phrase as "bad-move scenario", but this is probably an error.) The phrase "Bad Wolf" is a recurring theme in the 2005 series. The Face of Boe is revealed to be from the Silver Devastation, which is where Professor Yana reveals he is "from" in the episode "Utopia".
The Doctor tells Jabe that he was once on another "unsinkable" ship and wound up clinging to an iceberg, an apparent reference to having been on the RMS Titanic when she sank. Which incarnation of the Doctor did this is not specified, although the Seventh Doctor was on board the Titanic in the Virgin New Adventures novel The Left-Handed Hummingbird by Kate Orman (which is of uncertain canonicity). He did not, however, wind up on an iceberg in that story. In the Fourth Doctor story The Invasion of Time (1978), the Doctor claims that he "wasn't responsible" for the disaster. In "Rose", Clive, a conspiracy theorist, shows Rose a photograph of the Ninth Doctor with "the Daniels family of Southampton", on the eve of their scheduled voyage on the Titanic. For an unspecified reason, they canceled their trip and survived.
The Doctor pilots the TARDIS to two time periods before its eventual arrival five billion years in the future: the year 2105, which he claims is slightly boring, and the year 12005, which he calls the New Roman Empire. The Doctor previously visited the 22nd century in The Dalek Invasion of Earth.
The "iPod" (a Wurlitzer jukebox) that Cassandra unveils plays "Tainted Love" by Soft Cell and later "Toxic" by Britney Spears. "Toxic" was not actually released as a 7" 45 rpm vinyl single. The production team mocked up a 7" single for use in the episode.
Jabe's scan of the Doctor displays an animation by Drew Berry of translation, a process wherein a protein molecule is synthesised according to the genetic code carried by messenger RNA. A production sketch of the scanner drawn by Matthew Savage shows a scan of the Doctor indicating nine different DNA samples — one for each incarnation.