Roots: The Thing (alien DNA infecting and parasitising humans), Straw Dogs. There are references to the Sweet, Shirley Temple, Pina Colada, Man About the House, Sally Thomsett, Hai Karate, Sainsbury's, Sherlock Holmes, Slade, Bambi, George Carter and The Sweeney, Nimble, Slimcea, Mother's Pride, Harry Nillson, the Osmonds, and Dad's Army. There is a couple named Terry and June.
Goofs: Taking a cue from Ian Marter's novelisation of The Ark in Space, Wirrn is spelt 'Wirrrn'.
Continuity: The Xaranti are a species of intergalactic scavengers with no particular cultural or technological identity of their own. They are parasites, and move through space in the hijacked vessels of other species and perpetuate their own race by infecting other species, which causes a highly aggressive infection that forces the victim's body to transform. The infection takes the form of telepathic suggestions encoded at the molecular level and transforms the host by psychologically convincing it that it is transforming. As a result, the Xaranti "queen" can withdraw the contagion, and the metamorphosis, telepathically. The Doctor persuades the Xaranti to leave Earth and restore those humans only partially transformed by forcing himself to believe that he has developed an antidote, which means that it functions as an antidote, and then threatening to release it on Earth unless the Xaranti withdraw. As the Xaranti absorb other species physically, they also absorb their knowledge. They store the memories and knowledge of the beings they absorb, process it, and produce it in physical form as colourless secretions, which merge to form a giant communal mind that acts as a controlling intelligence for the Xaranti warriors. The Xaranti are originally from an unnamed planet in the Tau Ceti system, which was destroyed several centuries ago during their war with the Zygons (see Terror of the Zygons, The Bodysnatcher). Although both Xaranti and Zygons are now nomadic, their conflict has continued. In humans, infection by the Xaranti causes a physical change that includes the protrusion of dozens of sharp black quills from people's flesh. Adult Xaranti have bull-sized bodies and eight jointed legs, plus a scorpion-like tail and multiple eyes. They are arthropods with black carapaces. Their ship contains cannibalised parts from seven different technologies, and was original a Morok battle cruiser (The Space Museum). Mature Xaranti always infect rather than kill members of other species, unless they are old or infirm. They can detect cancer in human victims and kill anyone suffering from it.
According to the Doctor, the Moroks are so proud that would rather die than use another species' technology to repair their own. He knows a little about Morokian architecture. Morok battle cruisers have reflective melganite shielding that can withstand nuclear warheads.
Following the events of The Green Death, Mike Yates has been suffering from bouts of depression, as a result of which the Brigadier ordered him to undergo a course of pathological assessment and take some compassionate leave. His psychologist is called Dr. Cutler. Mike is now carrying out intelligence work for the Brigadier in Tayborough Sands, investigating reports of a strange light that came down in the sea twelve days earlier. Normally, the Doctor used to undertake such investigations, possibly out of boredom. During the sixth months since The Green Death, the Third Doctor has largely been making solitary jaunts in the TARDIS, often for several weeks, and was off Earth three months earlier when Mike's problems came to a head. Mike arrives in a Tayborough Sands with a suitcase containing an army-issue toiletry bag, some clothes, a file on his assignment, a chunky two-way radio, a Colt .45, and a psychology text book that he has been reading. Both the Doctor and the Brigadier have explained the fundamentals of regeneration to him, but he doesn't appreciate just how big the change can be until he meets the Fifth Doctor here. Mike owns a red Spitfire and is seconded a Ford Escort from UNIT's motor pool. Mike's call sign here is Greyhound Three: the Brigadier is Greyhound One.
The Brigadier meets the Fifth Doctor here [a fact that he presumably forgets as a result of the events of No Future]. He is infected by the Xaranti here.
Mike considers Sergeant Benton to be a good friend. Benton started flicking through Mike's psychology text book, but returned it to his desk with a troubled expression. He meets the Fifth Doctor here. The Xaranti infect Benton here.
The Doctor again adopts the alias Dr. John Smith. He lends Turlough a carpet bag during their stay in Tayborough Sands. He buys a '99' ice cream with glittering purple shells and eats half of it. The Doctor's Image Reproduction Integrating System (IRIS) is in a cobwebbed cupboard in the TARDIS - the Doctor notes that the last time he used it, somebody died (see Planet of the Spiders). He hasn't encountered the Xaranti before but recognises them. He eats chocolate bourbons and carries a small device shaped like a compact that allows him to monitor diagnostic programmes running in the TARDIS. The Doctor is able to make limited telepathic contact with the Xaranti. A Xaranti buries its sting in him, just above his collar bone, as a result of which he is infected by the Xaranti.
Tegan still distrusts Turlough. She once spent a happy weekend in Brighton with Aunt Vanessa (Logopolis) and used to go sailing off the south coast with her Grandfather [Verney - see The Awakening]. She last saw her grandfather just before he was about to move house and had promised to visit him as soon as she returned from Amsterdam (Arc of Infinity). She orders a glass of white wine in the Captain Cook. She's attracted to local policeman Andy Weathers and briefly wonders what life would be like if she decided to stay with him: they manage a date before he's turned into a Xaranti hybrid. She can swim. The Xaranti infect her here
Turlough claims that he is trying to make amends for working for the Black Guardian. The Doctor has mentioned UNIT and the Brigadier to him.
The TARDIS' in-built ability to pick a safe landing spot and thus avoid materialising underwater or in solid rock allows her to find a submerged spacecraft and materialise on board. In addition to the Cloisters, the TARDIS contains what appears to be a narrow, cobbled Victorian street, complete with starry night sky.
UNIT soldiers named here include Corporal Burke: a Xaranti kills him.
The Prime Minister is male, and is apparently the same one who spoke to the Brigadier on the telephone in The Green Death.
Links: Tegan recalls Turlough working for the Black Guardian (Mawdryn Undead) and recent events on Sea Base Four (Warriors of the Deep) and mentions being possessed by the Mara (Kinda, Snakedance). She recognises the Brigadier from Mawdryn Undead and The Five Doctors. Mike mentions the Master and recalls Daleks (Day of the Daleks) and Autons (Terror of the Autons). In a nod to The Invasion, Tegan yells "You... you... you... men!" at the UNIT soldiers. The Xaranti-infected Brigadier muses that Daleks, Cybermen and Movellans (Destiny of the Daleks) are impervious to infection. Some of the technology on the Xaranti ship may be Kraal in origin (The Android Invasion). The Doctor compares the Xaranti to the Wirrn (The Ark in Space).
Location: Tayborough Sands, [July 1972, six months after The Green Death].
Unrecorded Adventures: The Doctor has apparently visited Tayborough Sands pleasure beach before.
The Bottom Line: "We are all Xaranti". A by-the-numbers traditional invasion/possession storyline, with lashings of horror. As with the Zygons in The Bodysnatcher, Morris has clearly put some thought into the Xaranti, but the supporting characters are largely forgettable. The addition of UNIT serves little purpose, since only Mike gets any decent characterisation, and Turlough is utterly wasted.