A longshanked rascal with a mighty nose!
— Irongron describes the Doctor
An intrepid investigative journalist
, Sarah Jane Smith, infiltrates a secret research centre
where a number of top scientists are being held in protective custody while UNIT investigates the disappearance of some of their colleagues.
The Doctor follows the trail back to The Middle Ages
in the TARDIS; unbeknownst to him, Sarah Jane has stowed away on board. It seems that a robber baron called Irongron has made a deal with Linx, a Sontaran of the Sontaran Army Space Corps. Linx gives Irongron advanced weapons in exchange for time and shelter while repairing his damaged spacecraft. The kidnapped scientists are working under hypnosis to help.
The Doctor helps local lord Sir Edward of Wessex to repel an attack by Irongron's men, then drugs the food in Irongron's castle in order to remove the advanced weapons while they sleep. With the help of one of the scientists, the Doctor then sends the scientists back to the 20th century.
Linx kills Irongron and is about to leave when he is shot in the back of the neck with an arrow by Hal, one of Wessex's archers. Turns out that's the only weak spot on a Sontaran's armour - the "probic vent" - and he dies. The Doctor, Sarah and Hal escape before the ship can explode and destroy Irongron's castle.
An official BBC radio play by Barry Letts, "The Paradise Of Death"
, takes place between this episode and the next and stars Three, Sarah Jane and the Brigadier.
- Achilles' Heel: The probic vent.
- Anachronism Stew: It's implied that the action may be taking place pre-1066 ("Wessex," as a place name, was quickly dispensed with after the Norman Conquest), but the armor and weapons look to be anywhere between the 13 to 15th Centuries.
- Blasting It out of Their Hands: Once by Linx with his hand laser, and more impressively, Hal shooting a sword out of Irongron's hand with a bow.
- Blind Without 'Em: Prof. Rubeish. He fashions himself a monocle using Linx's equipment.
- Bullet Proof Fashion Plate: After spending days in the middle ages, exercising (and presumably sweating) and rolling around in the dirt and straw, the Doctor's clothing is still immaculate.
- Call Forward/ Call Back: The Doctor remembers the last time he met a Sontaran, but the actual events behind the meeting wouldn't be shown on TV for another 20 years.
- Chandelier Swing: The Doctor does one during a fight with Irongron's men.
- Cut His Heart Out with a Spoon:
Irongron: I'll chop him up so fine, not even a sparrow will fill its beak!
- Evolving Credits: This episode debuts the opening sequence used until Three's finale, when it was modified to become Tom Baker's intro for all but his final season.
- Fish Out of Temporal Water: Sarah Jane.
- Getting Crap Past the Radar: When the Doctor says he has to go find a young girl (Sarah Jane), Prof. Rubeish says to himself: "Young girl? Should have thought he was a bit old for that sort of thing."
- Going for the Big Scoop: Sarah Jane.
- Imperial Stormtrooper Marksmanship Academy: The knaves of Irongrad, and Irongrad himself, can't hit anything with their new 'star weapons'. Doesn't really discourage them from having fun with them, if a bit frustrating when actually in battle. Justified as older rifles weren't very accurate and the men firing them had normally fought with medieval weapons and had never seen a gun before. They decide to kill the Doctor via firing squad as aiming practice.
Irongrad: [amused] These knaves of mine aim so ill, Doctor, you are mayhap safer to stand still.
- Improbable Aiming Skills: Hal the archer can put an arrow through a probic vent from quite a ways away.
- Informed Ability: The Doctor's 'skilled' swordplay.
- Instant Sedation: Inverted. The drugged food takes a minute or so to knock out the people who ate it, but they are awakened with just a shake and a warning the castle is going to blow up.
- Intrepid Reporter: Sarah Jane.
- Laughably Evil: Irongron and Bloodaxe are a damn goofy couple of guys.
- Magic from Technology: Both Linx and the Doctor are seen as wizards by the locals.
- The Middle Ages: Sarah Jane seems to think it's The Dung Ages.
- Mind Control: Linx does this to the scientists.
- People in Rubber Suits: Linx.
- Pull the Thread: The Doctor, when he sees through Sarah Jane's cover story
- Scullery Maid: Sarah Jane poses as one to infiltrate Irongron's castle and drug the food.
- Slipping a Mickey: Sarah Jane drugs Irongron's men's food and drink.
- Wayback Trip, with elements of Giving Radio to the Romans: keeping firearms from developing centuries too early.
- Wham Serial: This serial names the Doctor's home planet, introduces one of the most popular companions of the series, Sarah Jane Smith, and also introduces recurring enemy race The Sontarans (although The Second Doctor has previously battled them)
- Where's the Fun in That?:
The Doctor: A straight line may be the shortest distance between two points, but it is by no means the most interesting.
- The Doctor pretty much states his MO when Sarah Jane Smith asks "Are you serious?"
"About what I do, yes. Not necessarily about the way I do it."
- Wrong Genre Savvy: See The Middle Ages above.
- Ye Olde Butcherede Englishe: When Sarah Jane starts speaking like this, Irongron's maid thinks she's nobility.