The TARDIS materializes. And out steps Dr. Elizabeth Klein. She's met with two guards, but she brushes them off because she's in command. She's already changed time and it is the year 2044 of the Galactic Reich.
But there is a fleet of Selachians, anthropomorphic shark-like beings in power suits, and they've launched a devastating attack with weapons beyond what they should have, and the only weapon Dr. Klein has to use against these overwhelming odds is her prisoner.
- Alternate Timeline: The Doctor (his mind at least) is from the timeline Klein left behind, and Earth is one that follows Godwin's Law of Time Travel. At the end of the story the Doctor visits the regular timeline's Dr. Klein.
- Apocalypse How: The Selechians attempt to destroy all life on Earth.
- Bittersweet Ending: The Doctor manages to swoop away in his TARDIS with Dr. Klein in tow, but Rachel (whom the Doctor is unaware of) who travelled with a version of the Seventh Doctor, is left on an exploding Moonbase alongside a Selechian warrior, both afraid to die.
- But for Me, It Was Tuesday: Rachel and Sam are two ordinary citizens, except Rachel has travelled with this timeline's Doctor, and mentions she's seen so many things this is just ordinary for her.
- Call-Back: The Doctor lists off in sequence meeting Klein in Colditz, the uprising in Kenya and the Vrill.
- When the Timeline has been corrected, the (non-Nazi) Dr. Klein working for UNIT mentions sightings of the Doctor in the previous stories, as well as the Shangri-La holiday camp in Wales and the "Shoreditch incident".
- The Selachians employ Transmat beams.
- Dr. Klein and General-Lieutenant Tendexter refer to past wars with Daleks, Sontarans, Autons and Zygons.
- The Doctor uses the memory of Jonas as narrated in "Klein's story".
- Not the first time the Doctor is on Earth's Moonbase.
- The Chessmaster: The Doctor is working off plans that alternate selves of him has concocted, and comes up with his own plan in between and pulls everything off.
- Conqueror from the Future: The Selechians are from the future as well as having more superior weaponry from further down their timeline.
- Foil: Klein's presence in this timeline is a sheer contrast to the Doctor's role in the true reality; where the Doctor just drops in to assist Earth against exceptional threats but lets humanity stand on its own, Klein is an 'official' employee of the Reich and has spent so long taking action to preserve the Reich that Earth is basically dependent on her to maintain its empire, where the Doctor has allies like UNIT, Torchwood and Sarah Jane to protect Earth in his absence.
- Giving Radio to the Romans: Well in this case it's giving Radio to the bipedal shark creatures. The Doctor (or rather an alternate version of him) gave the Selechians technology from their future.
- Godwin's Law of Time Travel: The Third Reich has become the Galactic Reich.
- Have We Met Yet?: Klein is really unsure whether or not the Doctor she keeps prisoner is one she's met before.
- Ignorant of Their Own Ignorance: The Doctor appears to be unaware that he has an 'agent' in this new timeline in the form of Rachel, who travelled with his other self, and only even learns she exists when Klein mentions her at a point when it's too late for him to try and look for her.
- The Mole: Rachel is one for the Doctor, and Sam is one for the Selachians.
- "Not So Different" Remark: Klein says this to the Doctor, that both are callous about the events of aborted timelines.
- Playing Both Sides: The Selechians are following plans the Doctor left them, a 100 years into their past.
- Ret-Gone: Happens and has happened several times with people outside of the TARDIS and its crew of "Temporal Affairs". The Doctor eventually inflicts this upon Dr. Klein to stabilize the Web of Time.
- Ripple-Effect-Proof Memory: The Doctor's mind has tumbled through several different timelines into another body, but he remembers the events that brought him there (But not the past experiences of the Doctor's body he inhabits)
- Set Right What Once Went Wrong: Klein's department of Temporal Affairs literally goes back into the past repeatedly in order to use future knowledge to give to past versions.
- Shark Men: The Selachians are like, literally sharks in suits.
- Shout-Out: The Doctor (sarcastically) says in order to travel across the Moonbase by "Clicking their heels, and chanting there's no place like..."
- Taking You with Me: General-Lieutenant Tendexter activates a destruction sequence that will wipe the Moonbase off of the face of the planetoid in order to destroy the Sheleichan fleet.
