I think there’s more behind these walls than just a ghost.

The Avengers

4.14: Castle De’ath

A splendidly atmospheric episode from the pen of John Lucarrotti, his last for the show, brought to vivid life by James Hill, his first, Castle De’ath is one of the highlights of the fourth season, incorporating as it does some surefooted misdirection as Jock McSteed and Mrs Peel investigate a death in the loch.

Steed: I think there’s more behind these walls than just a ghost.

Mrs Peel: What are you going to do?

Steed: I’m going fishing.

Mrs Peel: What, in the loch?

Steed: No. In the moat.

The title might suggest Castle De’ath is broader than it is, for while there are liberal does of humour and the scheme itself (“It’s all to do with the price of fish”) doesn’t stand up to much scrutiny (the fish are scant as they’ve been driven to deeper waters by the ultrasonic waves of submarines using the loch for dodgy things), the actual dramatics are played fairly straight, and the characters, while colourful, are neither wacky nor eccentric. The deft balance of elements is emphasised by the teaser scene in which a man is being tortured – on the rack, no less – and the sound of bagpipes drowns out his cries.

Mrs Peel: How do you do, Mr McSteed?

Steed: Everyone calls me “Jock”. How do you do?

Mrs Peel: You don’t have a Scots accent.

Steed: I was carried south by marauding Sassenachs when I was a bairn. But this is my spiritual home.

The duo’s assumption of identities is always good value, on this occasion particularly so. Steed is already installed at the castle upon Emma’s arrival, posing as the aforementioned Jock McSteed, rocking a natty kilt and researching a book on the disgraced thirteenth laird, Black Jamie, who was walled up in the east tower for his treachery and whose ghost still walks the castle, “playing the lament of Glen De’ath on the bagpipes”.

Steed: Isn’t it time we dropped in on the old fella?

Ian De’ath: No.

Steed: He must be lonely.

Ian De’ath: Walled up until doomsday was his sentence and until doomsday he’ll stay there.

Steed seeks the permission of the current laird, Ian De’ath (Gordon Jackson, very much in demand at this juncture, appearing in both The Ipcress File and Those Magnificent Men in Their Flying Machines in the same year), to go fishing in the loch (“Just as long as you’re not one of those aqualung people” Ian tells him; “Water is the fish’s habitat, not mine” Steed replies).

Except that Steed does, of course, end up getting wet. Spied upon by right-hand caber tosser McNab (Jack Lambert), he gets the better of them for a while, pretending to fish behind some foliage while he dives in the moat, but is summarily descended on upon surfacing (or, at least, his stunt double is; he also earns his fee very evidently during the climactic swordplay with Robert Urquhart’s Angus De’ath).

Yes, this is one where all eyes are on the severe and traditional Ian as the instigator of the diabolical plot, but it’s actually his free-spirited brother who’s responsible (although, why Angus is inviting all and sundry to stay if he's trying to keep his scheme a secret is anyone's guess). You might suspect this in a standard story, but we’re so used to The Avengers laying it all out on a plate that the deception works quite successfully.

Steed: (appreciating the portrait of Black Jamie) Fierce looking fellow, isn’t he?

Ian De’ath: You didn’t hear him last night?

Steed: Does he give regular concerts?

One wonders what Lucarotti’s source for spook material was, given that he ascribes as suspicious its erratic activity (“Unusual for a ghost. They usually operate a regular schedule”). Perhaps Steed is an amateur parapsychologist? While the episode doesn’t enter into full-on Scooby Doo territory, there are more than sufficient funhouse trappings, including an iron maiden in the basement with a secret door (that does for Angus during the final chase when it jams) and a four-poster bed with a cement canopy that manages to crush Steed’s bowler but not its intended.

Ian De’ath: You didn’t notice anything? Nothing at all?

Steed: Only the bed. Gave me a touch of claustrophobia. I spent the night in a chair.

Steed is, of course, unstintingly cheerful about the close shave (“They’ve got a spot-on service here. Tried to press my best shirt last night – while I was still wearing it”). Once he is captured and the mechanics of the scheme are revealed, the detail is a little on the superfluous/impenetrable side; as far as I can tell, we’re left to fill in the blanks of what exactly they’re up to with these two-man submarines (as McNab says to Steed “Your guess is as good as mine”; “I should think, slightly better” comes the reply). Steed correctly surmises they can’t’ just shoot him (“But the wee hole would show when they found my corpse in the loch”) and manages to escape his shackles with a lucky ricochet causing the sub pen to flood (“Going rather well”).

Roberton: The duty engineer’s been attacked.

McNab: Attacked?

Roberton: No, not him a woman.

McNab: A woman?

Steed: Bless her.

Mrs Peel is representing ABORCASHAATA, the Advisory Bureau on Refurbishing Castles and Stately Homes as a Tourist Attraction, hired by Angus much to Ian’s disdain. She’s particularly keen on checking out the dungeon, on account of Steed’s titbit (“Did you know that frogman was four inches taller when he was dead than when he was alive? He’d been on the rack”). Which means she gets jumped by heavies the first time (“Lean on me, Mistress Peel, as much as you like” invites Steed, before asking “Was there a rack down there? In good racking order?”)

On the second occasion, she is locked in all night in her nightie, causing Steed to astutely observe “I think we’ve been rumbled”. She also, during the final fight, kills a bad guy with a crossbow bolt. I don’t know: shotguns, crossbows. Mrs Peel’s really rather violent. Talking of which, I don’t think we’re fully clear if Ian dies from taking Angus’ knife to his chest. If so, it seems a little excessive.

Angus: Ay, Ian. You certainly work hard at this canny Scots bit, don’t you?

The episode’s full of lovely little moments, be they atmospheric (Steed noticing the vibrating wine glass during dinner) or amusing. At one point, he’s doing the Highland Fling in his bedroom while Mrs Peel plays miniature bagpipes. Later, or earlier, at breakfast, he’s dubiously contemplating his porridge when Ian advises “You’re right, man. There’s not enough salt on it” before liberally applying the same and offering Steed the cellar. He quickly passes it on to Angus.

It doesn’t look as if Macnee or Rigg got within a hundred miles of Allington Castle, if their conspicuous doubles are any indication, but it makes for a very nice slice of scenery and the seams showing fails to dampen the verve of the proceedings. The “walk-off” is good fun too, in which fishing comes up again. “What, in those clothes?” asks Emma of Steed’s immaculate suit. He promptly drives his – amphibious – car into a nearby loch.