• title card: white all caps text reading ‘THE BIG THINKER’ superimposed on a croner of the lab, showing a maniframe computer rack and cooling pipe
  • Dr Kearns plays cards, unaware that his mathematical ability will not help him in a rigged game
  • Dr Clemens is found dead in one of the ducts, Dr Kearns peers in from the far end
  • Cathy and Steed hold Broster and Clarissa at gunpoint after disarming them
  • Farrow sees his own name on the printout identifying the killer
  • Steed’s bag is packed for a mission in Tel Aviv and tagged with his Carruthers alias

Series 2 — Episode 12
The Big Thinker

Teleplay by Martin Woodhouse
Directed by Kim Mills

Production completed: 13 December 1962. First transmission: 15 December 1962

TV Times summary

Steed hunts an informer only to find that he himself is number one suspect

Plot summary

The super-computer Plato is being sabotaged and someone seems determined to kill the scientists involved. Mrs Gale is assigned to help Kearns overcome his gambling problem, since he is vulnerable to blackmail and some enemy agents are trying to lean on him. Meanwhile, Clemens has been murdered after discovering who the saboteur is and the truth is stored in Plato’s memory banks. Kearns and Cathy are trapped in the computer after further sabotage and are saved i nthe nick of time. When they emerge, Dr Farrow tries to stop Plato from revealing he is the killer, but is electrocuted in the attempt.

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Prologue

Dr Brensall (Johnson Bayly) is working on a computer housing and suddenly notices thick white smoke pouring from a cooling pipe, he rushes over the secure the leak - the pipe comes away and he collapses, coughing, to the floor.

Act 1

Catherine Gale (Honor Blackman) is shown in to the computer lab by Dr Clemens (Walter Hudd), who tells her she’s caught them in the middle of a breakdown. He adds that the whole building is the computer, ‘Plato’ and points out the refrigeration ducts. She’s hoping to use the computer to translate dead languages but he explains they’re still at the experimental stage when Dr Farrow (David Garth) comes in and greets Cathy, then tells them they’re still unoperational; Brensell’s not in yet and the ‘boy wonder is at his best, which doesn’t help’.

They enter to find the boy wonder, Dr Kearns (Anthony Booth), shouting orders to Dr Hurst (Tenniel Evans) and Janet (Marina Martin) - verifying Plato’s computations by doing the sums in his head. He says the problem is in the freezer unit, which is Brensell’s domain - maybe a mouse has got lodged in the pipes. Dr Hurst tells Clemens that Kearns is becoming intolerable.

Mrs Gale approaches Kearns and he’s insolent, thinking her yet another VIP on a guided tour. Learning she has brains he becomes all charm but loses interest when she introduces herself as Mrs Gale - it’s rekindled when she says she’s a widow. He asks her out but she declines when he callously says it would only be “little blue eyes”, indicating Janet, otherwise. Kearns decides he can’t wait for Brensell any longer and gets the key from Janet. They enter the central unit; inside there’s ice all over the machinery and while Kearns is shutting everything down, Cathy finds Brensell’s frozen corpse clinging to the computer.

Hurst notes that the door was locked and the gas detector and failsafe were both off; Farrow says maybe Brensell turned them off. Hurst wants proper security, not just the police, which Farrow dismisses. Clemens comes in and tells Hurst that running a secure establishment is like “fighting a boa constrictor”. Farrow allays any fears Hurst has about Cathy telling the press, saying she’s a scientist and wouldn’t tell anyone.

She is of course telling John Steed (Patrick Macnee) - Hurst is in a panic and wants MI5, the Navy, anybody, to come in.

STEED: You he can have. Not me. I’m off to the Middle East tonight.

Steed queries Farrow’s presence, being an astronomer, and is told he’s using Plato to check calculations on star velocities. She tells him she’s going to a party that night with Kearns to cultivate the contact, and concedes he’s an objectionable young man.

CATHY: And you’re keeping right out of it?
STEED: Yes. But don’t let me stop you, Mata Hari. You just go right ahead. Send me a postcard.

Cathy tells Steed the computer is 100 times faster than anything else and Steed suggests it could be used for missile interception - high-speed flight path calculations, which makes it a prime target for sabotage. He tells her to keep an eye on Kearns, as he’s ripe for subversion.

Kearns takes her to a poker game where Broster (Allan McClelland) and Blakelock (Ray Browne) are at the table with Clarissa (Penelope Lee). Kearns orders Cathy a gin and tonic and says he’s an average player but has an edge because he can calculate the odds and remember the cards.

Broster has a quick conference with Clarissa, telling her to find out who Cathy is while they give Kearns “a bit of a heavy evening”. Kearns sits down cockily to the next game and Clarissa sidles up to Cathy, telling her she might as well have another drink as he’s gone for the evening - she summons Nino (Clive Baxter) and winks at him, and he hands Cathy a drink. She sniffs it and smiles wryly as she puts it down again.

Kearns wins easily at first and tells Blakelock and another ‘small gun’ to make way for the big boys - two determined looking men. Kearns ignores Cathy’s advice to stop while he’s ahead, sits back down and ruffles the deck, carelessly drinking from a glass Nino has just placed before him...

Steed has just fed Sheba when Cathy returns home, carrying a sozzled Kearns, who tries to punch Steed before collapsing on the divan. Cathy asks him why he’s not in the Middle East then tells him that Kearns lost £500 at the poker game, the other players ganging up on him. She tells him they fixed her drink and he says, “Nice people!”. Steed tells her to apply the pressure on Kearns - so the other side can’t - and gives her a cheque for £500; Cathy tells him she thinks Broster and Clarissa might be the oppposition - or they might just be gambling sharks.

The next day, Kearns is rude to Janet again and Clemens forces him to apologise, or leave the lab. Clemens consoles her and she’s staring mournfully at Kearns as he feeds a tape to Plato when Cathy arrives. She’s told they’re working on ballistic calculations for Farrow - just as Steed predicted!

Kearns comes over and says it wasn’t a good night for either of them, then notices Janet is worried about the results coming out of the computer. He checks the equipment and burns his hand on the casing. He tells Janet to switch off but nothing happens when she does, so he starts pulling the fuses out. When Plato keeps going regardless, Cathy takes over removing the fuses while he goes for the master switch. He pulls it and Cathy is electrocuted and collapses...

Act 2

Later, Broster tells Clarissa the computer is out of action for a few months and the minor setback of Cathy paying the £500 won’t stop them; Kearns will be more receptive after a few more IOUs. Nino announces Cathy, who gives Broster cash for Kearns’ IOU.

Broster asks her to dine with him but she declines; he offers a flutter for the money instead and she accepts - one card draw. She tells him to go first and watches carefully as he draws a Queen - she repeats the manoeuvre and draws the same.

CATHY: Snap! Would you like me to try for an ace? I expect you trim the short sides of the aces.
BROSTER: Clever, dead clever.

Broster reaches for the money - but Cathy hits his wrist with a sharp karate chop and picks up the money then bids him goodbye.

Clarissa and Blakelock are searching Cathy’s flat when she returns home - he hides behind a bookcase while Clarissa begs not to be reported to the police, claiming that Nino thought Cathy was a policewoman and she was hoping to find out. Cathy tells he she doesn’t believe her and offers her a cup of tea - she goes around the corner and surprises Blakelock, but Clarissa escapes while she deals with him.

The next day, Hurst is in a flap about getting security services in but Kearns dismisses the idea of men in trenchcoats and hats, saying there was a fault in the test tape and that was the cause of the power problems. The other staff enter with Cathy, and Clemens asks Hurst for a private word after telling Cathy not to play with fire again. Farrow confides to Cathy that Hurst thinks they’re being sabotaged - the test tape contained instructions to erase all the memory banks instead of doing further calculations.

Kearns tells them whoever last put in the fuses put in the wrong values - then says he was the last one to put in the fuses! Janet anxiously asks him if he did make a mistake and he tells her they’re being got at. She tells him he doesn’t really care at all and he kisses her brusquely, then goes back to work as though it had never happened. Clemens enters and tells Janet to go home, then tells Kearns he’s disrupting the project - not sabotaging, that’s a separate issue - and is relieved of his duties for the time being. Kearns refuses to go:

KEARNS: I’m not going, you know.
CLEMENS: I beg your pardon?
KEARNS: What did you hire me for? Hmm? Not my manners, surely. You hired me because I understand Plato. I know what makes him tick. Nobody else does! You mean to say you’re going to hand over Plato over to - to that bunch of ha1f-wits? All right, let’s take Farrow. He’s all right, if he sticks to astronomy. Then there’s Hurst. (LAUGHS) That’s a laugh! Huh! He’s afraid of his own shadow! So what does that leave us? That leaves us with our dear little Miss Lingfield here. Oh, she should be at home in someone’s bed, not - not pushing buttons here. No, she can get together with that, with that anthropology bird and talk knitting.Listen, you can all talk knitting for all I care. All right, look, if you want to do it, go ahead, go ahead, chase your spies, all right? — but leave me alone, I’ve got work to do. If you want to get rid of me, if you want to throw me out, bring your security men to do it for you. Okay?
CLEMENS: You just made my point, Dr. Kearns. Goodnight.

Cathy enters the office to get a coffee and Janet asks her what she’s really doing there - but it’s her floundering romance with Kearns she’s worried about. Cathy tells her she’s not interested in Kearns but if Janet is, she needs to stop him gambling before he makes a fool of himself or loses his job. Cathy and Janet go back to the computer block, where Kearns is still working; he reenters the centre just before them and finds the inner door locked, and the telephone cord severed. He’s just retrieved the key from Dr Clemens’ office when the girls arrive, finding the lights off and a strange smell in the air. Kearns explains he’d left the lab unlocked and his key inside, and he indicates the disconnected telephone - and all three enter the lab together. Inside, the heat is stifling, and the electrics are haywire again. Kearns picks up his key then climbs a ladder and he finds Clemens’ body in the air conditioning duct.

Act 3

Next morning, Cathy tells Steed security consider both deaths accidents. Brensell was gassed, frozen or both; Clemens was killed by a bare wire shorting out against the air trunking. When Cathy says Kearns has vanished, Steed is irate, saying a scientific establishment has turned into slaughter on Fifth Avenue and their prime lead has vanished in a puff of smoke.

Broster and Clarissa are debating where Kearns has got to, he considers phoning Cathy to find out but changes his mind and they show up at her flat instead. Broster tells Cathy they have Dr Kearns and he’s planning to defect. Cathy refuses to believe them and they draws guns - Clarissa’s is a gas pistol and Broster says it makes less mess. They’re demanding Kearns’ whereabout when Steed enters, jabbing his umbrella into Broster’s back so he thinks it’s a gun.

STEED: Oh dear, oh dear. The amateurs are still hard at it! My dear, those are quite ineffective beyond a range of three feet.

The villains are disarmed and Steed calls the police, using the alias Carruthers1 then tells Cathy to hand them over as he once again claims he has to catch a plane to the Middle East.

At the lab, Hurst ushers Janet and Farrow out, telling them it’s a complete shut-down and he doesn’t care where Kearns is, that is now a police matter. He’s ordered no entry to the unit without a pass and adds, “that should mean we shan’t see any more of your Mrs Gale” as they depart; Cathy comes out of a side room and smiles, then enters the main unit. She fends off Kearns who says he hid inside the unit and never left, fearing he’d be next on the list.

He theorises Clemens was lured into the air tunnel by the combination of locked door, disabled phone and small gas leak - Clemens would have known he could escape by the trunking. Someone enters the outer offices just as Kearns goes on to suggest that Clemens would have put the saboteur’s name in Plato’s memory banks; after the last sabotage, the memory was entirely wiped so anything in there must have been left by Clemens, and he starts testing the banks for data. He finds it but the fire door closes on them before they can go to see what it says.

Outside, Farrow removes the output from the printer and crumples it up before turning the temperature controls right down. Inside, Kearns has realised the door was closed from the outside rather than by a safety trip. When Cathy notices the temperature dropping he tries to break a pipe, burning his hands on it. They then try to use Plato to call for help and Steed, who’s just entered, rushes to the printer when it begins typing “SOS” over and over.

Steed calls security and is struggling to make sense of the controls when Hurst and Farrow enter. He tells Hurst to open the door to free Cathy and Kearns and they emerge, almost numb with cold. Kearns tells Hurst Plato can identify the murderer and they’re about to re-run the programme when Farrow grabs a lead pipe. He destroys Plato but is electrocuted and killed when the pipe hits the memory banks.

Steed makes a cup of hot chocolate for Cathy at her flat and asks her to look after Sheba for a few days. “Don’t tell me”, she says, "the Middle East?" He takes the IOU from her, but graciously tells her to keep the £500 and buy herself a fur coat, just in case she gets cold again.


  1. He uses the alias Carruthers again in Killer Whale.

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