BASIC PLOT
An invasion is underway on an oil rig. In the distant future, a race of beings encounters an impenetrable spaceship. The Master is planning to escape his top-security prison on Earth. These events are far more related than anyone realises.

DOCTOR
Third.

COMPANIONS
Jo Grant, Brigadier Lethbridge-Stewart, Captain Yates, Sergeant Benton.

MATERIALISATION CIRCUIT
Pg 53 The TARDIS is in UNIT HQ at the beginning of the story.

Pg 164 On a beach at Durlston Heath, during Viking times.

Pgs 202/231 On board the Consolidator, billions of years in the future (page 201).

Pg 269 Praxilion, ten million years earlier.

Pg 348 Praxilion, millions of years earlier.

Pg 353 UNIT HQ, London, present day.

PREPARATORY READING
A familiarity with the conclusion of The Daemons would be helpful.

CONTINUITY REFERENCES
Pg 21 "Certainly the young woman pressing her face to the helicopter's window had not had much of a clue about what she was getting into when she was first assigned to UNIT. Time travellers, ancient enemies from beneath the Earth, forces and factors beyond the planet" The ancient enemies from beneath the Earth are likely the Silurians. But see Continuity Cock-Ups. The factors beyond the planet refers to Colony in Space, Jo's first adventure in the TARDIS.

Pg 24 "Oh - and by the way - that inane humming happens to be a rendition of one of the greatest tragic operas in the history of the Venusian arts." The Curse of Peladon, Venusian Lullaby.

Pg 25 "I used to know a MacCrimmon once - awfully decent fellow." Jamie MacCrimmon (The Highlanders et al).

Pg Pg 55 "Nothing that you or I have ever encountered fits the bill. And the fact the Daleks aren't involved may be the last piece of good news I have for you." This suggests the Brigadier has met the Daleks, setting the story after Day of the Daleks.

Pg 57 "I am known universally as the Master" Terror of the Autons.

Pg 64 "If it's not the Yeti, it's the Cybermen; if it's not them, it's the Autons or the flipping Silurians." The Web of Fear, The Invasion, Spearhead from Space, The Silurians. See Continuity Cock-Ups.

"And yet the Master and the Nestene Consciousness were working together to direct the Auton invasion" Terror of the Autons.

Pg 69 "Just a moment, Susan..." An Unearthly Child et al.

Pg 73 "But if a word of this gets out to him - or to anyone else in UNIT, or Geneva, or C19 - I'll need look no further than you for the source of the leak." C19 were mentioned in Time-Flight and featured heavily in The Scales of Injustice.

Pg 76 "Bessie, the Doctor's bright yellow Edwardian roadster, made an incongruous sight as it pulled up at the heavily defended checkpoint." Doctor Who and the Silurians et al.

Pg 116 "Where there was life there was hope, always and forever." One of theThird Doctor's common sayings (eg Monster of Peladon, Planet of the Spiders).

Pg 156 "What you are driving towards are alien creatures, no different from the Axons or Autons - you understand?" The Claws of Axos, Terror of the Autons.

Pg 161 "'Aye,' Irwin said. 'And the Clangers, they're real as well." The Sea Devils.

Pg 166 "The Doctor struggled with it for a few moments, then dug out his sonic screwdriver." Fury From the Deep et al.

Pg 174 "You can't do your usual bargaining with the enemy, Master. It may have worked with the Axons and the Nestene Consciousness, but they needed your cooperation." The Claws of Axos, Terror of the Autons.

Pg 194 "An Ogron would have tried counter-gravitic torque equalisation." Day of the Daleks.

Pg 195 "This was still not independent time travel of the kind the TARDIS used to be capable of, before the Time Lords banished the Doctor to Earth" The War Games, Spearhead from Space.

Pg 199 "Back before he had to bother himself with Yetis or Cybermen or strange men in blue boxes." The Web of Fear, The Invasion.

Pg 203 "The Sild time ruptures were beginning to cause local weather anomalies" Just like what happens in The Claws of Axos.

Pg 207 "Reminds me a little of Skaro..." The Daleks et al.

Pg 220 "It was no version of the Master that the Doctor recognised. A young man in a business suit, beardless, with a mop of boyish hair. His face, what the Doctor could see of it, seemed friendly and plausible. The face of a politician" This is the John Simm Master, aka Harold Saxon (Utopia, The Sound of Drums, et al).

Pg 223 "'My guess,' the Doctor said, 'is that the Sild have messed things up so thoroughly that all classes of time paradox are now possible. Even a type three Blinovitch crossover."' The Blinovitch Limitation Effect was first mentioned in Day of the Daleks.

Pg 231 "He had even seen the Earth itself incinerated, as as the enlarging sun spread its envelope nearly all the way to the orbit of Mars." The Ark.

Pg 235 "Time dams, of a particularly crude and inefficient variety." The Pirate Planet.

Pg 260 "Generally incarnations were prevented from meeting, but that was not to say it never happened. In times of crisis, in moments of great cosmic emergency, those appalling hypcrites on Gallifrey had been known to bend the odd rule or two." The Three Doctors.

Pg 303 "A large creature, such as an Ice Warrior or a Judoon, would never have fitted within." The Ice Warriors et al, Smith and Jones et al.

Pg 316 There's a thing like a cactus that's probably a Zolfa-Thuran (Meglos).

Pg 320 "Where there was life, there was yet hope." The Monster of Peladon, Planet of the Spiders.

Pg 336 "Your precious Blinovitch would be spinning in his grave, if he were anything other than a myth." Day of the Daleks et al.

"Back to a miserable prison cell, with only a colour television for company?" The Sea Devils.

OLD FRIENDS AND OLD ENEMIES
The Delgado Master.

Pg 220 The John Simm Master, the Peter Pratt Master, Missy.

NEW FRIENDS AND NEW ENEMIES
Edwina "Eddie"MacCrimmon, as well as several Praxilions.

CONTINUITY COCK-UPS

1. Pg 17 "He would turn if off in a little while" Say what?
2. Pg 21 "Certainly the young woman pressing her face to the helicopter's window had not had much of a clue about what she was getting into when she was first assigned to UNIT. Time travellers, ancient enemies from beneath the Earth, forces and factors beyond the planet" Except that this is Jo Grant, who didn't encounter the Silurians. And this novel is explicitly set before The Sea Devils, so it can't be them.
3. Pg 37 "Jo smiled. We're not here to make life difficult for you Mr Lomax. It's just that something odd happened and you're our only witness.'" This is missing an opening quote mark but has a closing one.
4. Pg 58 "He was about to leave the man when he spotted the shortbread finger, still uneaten He dunked the biscuit into the half-finished tea" Huh?
5. Pg 64 "If it's not the Yeti, it's the Cybermen; if it's not them, it's the Autons or the flipping Silurians." And yet Mike Yates was not present in The Web of Fear or The Invasion. We'll be charitable and assume the latter two refer to Terror of the Autons and The Scales of Injustice, where he actually was.
6. Pgs 163-164 "If he had his calculations right, he should be able to use the residual energy from the time distortions to override the Time Lords' control of the TARDIS." Except that the Time Lords didn't just wheel-clam the TARDIS, they also took away the Doctor's knowledge of time travel - which he explictly regains in The Three Doctors, so he didn't have it here. So how can he fly the TARDIS?

PLUGGING THE HOLES [Fan-wank theorizing of how to fix continuity cock-ups]

1. McGinty isn't sure he's going to turn the radio of, so has "if" in his head.
2. There may have been a third group of ancient enemies beneath the Earth that we never saw.
3. Jo isn't sure whether she was thinking it or saying it.
4. The Master thinks of himself as God, so He often capitalises His pronouns in His own mind.
5. By a staggering coincidence, both the Yeti and the Cybermen invaded Earth again, only a few years after their previous attempts, in unrecorded adventures.
6. The Time Lords are actually helping him out, without his knowledge. The conveniently wipe his memory after this.

FEATURED ALIEN RACES
Pg 8 Praxilions, furry caterpillars bent into an upright L shape with redand white striped fur.

Pg 35 The Sild. They are blobs in glass jars affixed to the back of metal crabs, who attach themselves to other species to possess them.

Pg 227 A robot, as big as a house, with a spherical body and a spehrical heads with talons, pistons and probes.

Pg 316 A towering, grey-frred thing with two red eyes in the middle of its sternum.

A thing like a brain, moving around on three prehensile spinal cords.

A thing like a cactus (likely a Zolfa Thuran, from Meglos).

An alien made entirely from water.

A Quagulan, with glittering knife-edged armour.

A Social Craint, half organism, half unicycle.

A Mepuloid, multi-legged and sting-tailed, with a cluster of eyestalks.

FEATURED LOCATIONS
Pg 8 Praxilion, billions of years in the future (page 9).

Pg 17 Cromarty, Scotland.

Pg 26 The oil rig Mike Oscar Six, off Scotland.

Pg 21 A helicopter.

Pg 44 A trawler.

Pg 51 UNIT HQ, London.

Pg 71 Durlston Heath.

Pg 175 Eastmere.

Pg 203 A Hercules.

Pg 257 We get a flashback to the Doctor and Master as friends on Gallifrey.

Pg 269 Praxilion, ten million years earlier before the previous setting.

Pg 313 Aberdeen.

Pg 335 A flier.

Pg 349 Praxilion, millions of years earlier than the setting before.

IN SUMMARY - Robert Smith?
This is a great novel! It portrays the UNIT family really well and is especially interested in the Master, who's portrayed to perfection here. The Doctor is perfectly Pertwee, with a mix of doubts and bluster. The Sild invasion of an oil rig is a bog-standard teatime adventure, but there are some conspiracy hijinks and two excellent characters in Eddie and (especially) Tom Irwin. Mixing it up with the time shenanigans in the distant future and the plethora of Masters elevates it to something much more substantial. My major gripe is that the use of the TARDIS to flit about the universe is way too contrived. The author clearly wanted to set the action before The Sea Devils and yet have the TARDIS operational, but should have put more effort into making these work (or simply let go of one of the options). That aside, this is a textbook way to do a Missing Adventure: recreate what you need to and also push further than could have been done on screen. Recommended.