At the Bank of England, Penelope startles a police officer by suddenly appearing in front of him. She says she had to leave her car, and is now quite lost. She asks for directions to the Tower of London, as she'll know her way from there. The police officer says that's easy enough, but before he can say any more, Parker suddenly takes him out. Penelope asks that he hasn't hurt the police officer, and Parker says he hasn't -just a touch of chloroform.

The two then set things up. Parker drags the officer out of the way, and Penelope says a plastic explosive should take care of the door. Parker then deactivates the alarm, so Penelope gets the plastic explosives put on the door. Parker passes her the fuse, which she places down on the door. They then take cover, and the explosive detonates.

With the door unlocked, they enter the bank, and Penelope tells Parker the rest is up to him -he has plenty of time. Parker starts using a stethoscope to try and unlock a vault. Penelope starts clicking her fingers, so Parker asks if they could have a bit of hush.

Penelope says she's sorry, but if he just used a modern detector... Parker says that a stethoscope was good enough for his father, and his father's father, and before him, his... Penelope interrupts and says alright -it was just a suggestion! Parker resumes work, and as more time passes, he is able to finish what he's doing.

The door unlocks, and he opens it up. He says that their mission is completed, in two hours, twenty five minutes exactly. This is met by praises of the bank staff, who turn out to have been watching nearby. Penelope tells Lord Silton that they followed his instructions to the letter. Silton says that for years, the board of governors have refused his request for a new, modern up to date safe. Now he has positive proof that this strong room is just not good enough.

Parker is enjoying all the attention he's getting, and says he agrees that he has a rare talent. Silton says that the bank will get a new vault for this, and Parker says any time. Penelope says she thinks that will be all, and says they must be on their way now. She hopes Silton will be able to keep the dinner invitation, and he says he shall. Parker asks him if he will take care of any trouble arising after this incident. Silton says he'll answer for everything, but as Parker and Penelope leave, he wonders what sort of trouble Parker had in mind. Outside, the police officer has woken up, and is blowing his whistle.

As Penelope and Parker head back home, Penelope tells Parker she is pleased, and he has done extremely well. He certainly has a way with safes, so thank goodness so few people share his talent. Parker says that off hand, he can only think of one other expert capable of such a job. Penelope asks for this person's name, but Parker says it's of little consequence. The guy is retired, at least for the duration. But at Parkmoor Scrubs prison, one prisoner has just escaped!

The prisoner is the guy Parker was talking about: Light Fingered Fred. Sometime later, Penelope is on a video call with Silton. She says she's delighted that the new vault has been installed so quickly. She tells him they must talk about it more over dinner tonight. Silton says he'd love to, and hangs up.

At the bank, Lovegrove tells Silton that the Brinkley report is ready. Silton is surprised that report has already been done, and Lovegrove says Lambert was working on it. Silton knows that Lambert is the chap who absolutely buries himself in his work. He gets 10 times more work done than anyone else, so he could do with a few more like him. Silton then looks a picture of the bank, and says whilst it looks the same on the outside as it did centuries ago, but down here they have the strongest, most modern vault in the entire world. One does deplore change, but it is comforting to know what all of England's deeds, monies and documents are safely under lock and key.

Silton reveals that he is the only one with the key, which is an electronic one. He says he carries this key with him wherever he goes. Lovegrove then does a roll call, to make sure everyone is out of the vault. Almost everyone is present, other than Lambert. Another banker says that Lambert did leave the vault earlier. With everyone present and accounted for, Silton uses the key.

This causes the vault's door to close. Silton says they can rest assured that nobody will ever break into here. Lovegrove says the vault is a great engineering achievement, and he especially approves of the way the air is pumped out of the vault, as papers keep so much better in a vacuum. He asks Silton if he has the key, and Silton says it's in his case -a case that never leaves his side. Silton leaves, and tells Lovegrove he doubts that door will be opened for at least another two years.

However, Lambert is still inside the vault, engrossed in his work. The air in the vault begins to be pumped out, which is displayed on a monitor board. Later on, Lovegrove says they've checked everywhere else, but Lambert is still missing -perhaps he is locked in the vault!

Lovegrove tries contacting Lambert, but Lambert says he gave orders not to be disturbed, as the figures he's working on must be finished. He ends up putting his radio in a drawer and shutting it, hoping that he'll get some peace and quiet now. Lovegrove realizes Lambert is still in there, but has rung off. He looks at the air indicator and says that in another two hours, all the air will have been pumped out. They can't stop it, and they can't open the vault. Another banker says to contact Lord Silton, as he has the key. But Lovegrove says Silton has gone to a stately home, and he doesn't know where it is. He decides to use the emergency call system. Meanwhile, Silton has gone to Penelope's home, and says he still can't thank her enough for all she's done. Penelope says Parker must take most of the credit. Silton says he wishes he could find someone like Parker -knows his place, dresses well, he's the sort of person you could take anywhere.

Parker is busy drinking, and asks Lil if his grub is ready yet. Lil, the cook, says she only has one pair of hands. Parker thinks she's wasting her time here, as if she's got more hands, she would make a few bob in a circus! He wants to know what she's cooking for Penelope and Silton, but she thinks it's none of his business. He says he doesn't blame her for not telling him, as if he cooked like her, he wouldn't shout about it! Lil tells Nosey to listen here, but he says to show some manners -it's Mr. Parker, if she doesn't mind!

Lil tells Mr. Nosey Parker that she's been slaving over this all day. She's starting them off with a drop of consomme, which Parker thinks is a horrible load of old rubbish. Lil says then she's done a special escalopy receep, with all the trimmings. Parker thinks that's muck, that gives him heartburn just to look at it. Lil then says to finish things off she's done crapey suzettes and coffee. Parker says they're welcome to it, but wants to know what she's done for him. Lil brings him over a plate of stew, which Parker says is his favorite.

She also passes Parker a paper, as she knows he likes to read whilst he's eating. Parker is horrified to read the front page, which has a story about Light Fingered Fred escaping from prison! The garbage bin Fred is hiding in has been placed on a truck, which leaves the prison. The bin falls off the truck, and bounces across the road and into a field.

Fred survives, and pulls himself out. Meanwhile, Penelope says she can't tell Silton how pleased she is that he accepted her invitation to dinner. Silton says the pleasure is all his, as so rarely as he able to get away from his duties at the Bank of England. Penelope then summons Parker, and tells him he may serve coffee now.

Penelope asks Silton if he'd like Parker to take his briefcase, but he says no thank you -this brief case never leaves his side. He then hears a beeping noise and realizes it's the emergency call system. He's wanted at the bank immediately, and Penelope asks if this means the bank is being robbed. As Parker enters and hears this, it causes him to drop the coffee.

The coffee spills all over Silton, who calls Parker a clumsy nincompoop. He apologizes for the outburst, but that coffee was rather hot. Parker says he's sorry, he didn't know what came over him... it must have been a sudden shock. Penelope tells him to get something to clean up this mess.

Silton says he must ring the bank immediately. He uses a video phone to do so, and says they'll be able to find out the trouble. But outside, Parker is trying to listen in. He goes over to where the home's power controls are, and cuts one of the wires with some cutters.

Just as Lovegrove appears on the video phone, the power to it suddenly goes out. Silton says that they've been cut off, so Penelope summons Parker again. As he enters the room, the cutters fall out of his jacket, which are seen by Penelope and Silton. Parker claims he had been pruning the roses.

Penelope tells him to get the Rolls Royce out, as they're taking Lord Silton to London. She tells Silton they'll have him there in no time, as her car is capable of phenomenal speeds. But as they head out, Parker is driving very slowly. Silton says it's a very smooth ride, it feels like they're hardly moving. Parker says he can't understand why they're going so slow, he has his foot hard down. Penelope says she doesn't know what he's up to, but he needs to get them to London quickly. Parker speeds up.

Lovegrove says there's just 90 minutes left, and no sign of Lord Silton. He decides they must call for outside help, and one of the other banker is soon in contact with John in Thunderbird 5. John contacts Tracy Island, and Jeff tells him to brief Scott -there's very little time on this one. John says he'll clear the air and remain on standby.

As his sons enter the room, Jeff tells Scott to leave immediately. His destination is England, and John will brief him as soon as he's on his way. Scott boards Thunderbird 1, and takes off.

Tin-Tin contacts Scott and tells him his landing point is the City of London Heliport. Scott says he's received the details of the emergency from John, and requests Thunderbird 2 with pod 5. Jeff says request granted, but Scott says he reckons Virgil will need some help with this one. Jeff says things have been quiet on the space front, and decides to give Alan a chance to see some action. He then tells Virgil to go, and Alan will be joining him. Virgil heads off to Thunderbird 2.

Alan arrives via the passenger chute. Virgil selects pod 5, and then Thunderbird 2 heads down the runway and takes off.

Scott arrives in London, and lands on the heliport. He goes inside the bank, and whilst Lovegrove is glad he's here, he can't see what they can do unless they get the key. There's now only one hour left, but Scott says they're not often beaten. The equipment will be arriving any minute. Outside, Thunderbird 2 lands on the heliport.

John reports that Thunderbird 2 has landed safely. Scott has reported that due to the underground cables for communications in London, the Mole cannot be used. Tin-Tin thinks if they can't tunnel their way in, they'll never rescue that poor man. Jeff says not to worry, as the boys will burn their way through the door. In the bank, Virgil is trying to do just that.

Lovegrove promises it would take years to get through the door this way. Scott says it won't take that long with their equipment, but will it be fast enough? Meanwhile, Parker has arrived at a place called Lovers Leap. Penelope wants an explanation, and Parker says he seems to have lost his way. Penelope is shocked he's managed to not know how to get to London, and asks him to step outside, as she wants a word with him.

She wants to know why he is so intent on stopping Lord Silton from getting to the bank. She can see now that he was the one who put the video phone out of action... pruning roses indeed. She wants him to explain, and says she's waiting. Parker says that it all began the last time he was away. Penelope says if he means when he was in prison, and he says she can put it that way. It was when he was sharing a cell with a gentleman know to the trade as Light Fingered Fred, the only other soul capable of doing that safe job for Silton...

Fred once asked Parker what he was going to do when he gets out. Parker says he hasn't thought about it much. Fred thinks it's important, as it's only right that a bloke should have ambition. He doesn't want to waste these 10 years, he's going to learn from them. He's going to learn from his mistakes, and there comes a time in every man's life when he knows what he's got to do. He may have not been a friend of society up to now, but he's going to reform and settle down... just as soon as he's knocked off the Bank of England.

Parker can't believe it, is Fred saying he's going to rob the Bank of England? Fred says to mark his words: he shall break into the vault, and he personally will do the Bank of England! Back in the present, Parker says this emergency at the bank could be Light Fingered Fred carrying out his threat. Penelope says not necessarily, but Parker thinks it could be him. It wouldn't be right for him to be the one to ruin an old colleague's life ambition.

Penelope says they don't have time to argue, but if he feels like this, then she'll drive them to London. They get back in the car, and Penelope starts it up... and nearly drives them right off the cliff. She backs up and eventually spins the car around, before moving away at great speed. Parker repeatedly warns her about a tree they're approaching.

Penelope sees the tree, but turns so late that the car rebounds off of it. She then drives so fast that the car takes off when going over a bridge, but it lands on its wheels and keeps going.

Back in the bank, Scott tells Virgil and Alan to hold it. He shows them a map, displaying a plan of the vault. He says there is definitely a weak spot underneath, but Virgil reminds him that they can't tunnel in. Scott thinks they're beaten, unless headquarters can help. Lovegrove looks at the indicator, and says that there is just 30 minutes left. Inside the vault, Lambert thinks it's getting hot in here, but decides to finish things off before going home.

Jeff and the others learn from Scott that they can't cut through the door in the available time. Brains doesn't have any ideas, but Jeff thinks there must be an answer. Grandma Tracy says she thinks she knows what it is. She remembers that when she was a little girl, her grandma told her about the old London subway. Trains under the ground, something New York had as well, before this newfangled overhead monorail system. Jeff tells Scott to check and see if those tunnels are still in existence.

Virgil and Alan soon find the subway, and are in Piccadilly Circus. Alan thinks this sure is a change from being up in space. Lovegrove says 10 minutes is all that's left. Scott finds out there has been no news on the guy who has the key. Meanwhile, Penelope crashes the car through a bush, and Parker tells Silton that this is one of her shortcuts.

Virgil and Alan use hover bikes to make it to where they need to be, and start searching for the elevator shaft. Back in the vault, Lambert realizes he can hardly breathe, and decides he must get out of here. But as he goes to the vault door, he realizes it is shut -he's been locked in! He also knows that the air is nearly pumped out.

Alan and Virgil climb a ladder, and Alan says this is it. The air indicator falls to empty, and Lovegrove says there's three minutes to go. Virgil and Alan use some handheld drills to start drilling into a wall.

Penelope's group arrive at the bank. Penelope says that was a pleasant drive, and tells Parker she must do this more often. Lovegrove goes back to his desk, and thinks he must use his phone to call for help. Virgil and Alan finish drilling, and then place an explosive charge onto it. They then head off to take cover.

Penelope sees Scott, and asks what's happened. Lovegrove sees Silton, and tells him that Lambert is trapped in the vault. Scott says there's just seconds left, so Lovegrove tells Silton to use the electronic key -the key he always has with him in his briefcase, that never leaves his side. Silton realizes he's left it at Penelope's!

Parker asks Penelope for one of her hair clips. She thinks this is not time for flippancy, but he says he couldn't be more serious. They haven't built a safe yet that Nosey Parker can't open! Inside the vault, Lambert tries to contact International Rescue. But then, one of the walls is blown apart.

Virgil says they're through. Lambert asks who they are, and Alan tells him they're International Rescue. Lambert tells them he knew they were highly efficient, but this is ridiculous! The vault door then opens, thanks to Parker. He tells Penelope he's ruined her hairpin, but she calls him an old rascal.

Silton can't believe that the vault was opened with a hairpin, it's outrageous! Virgil and Alan get Lambert out of the vault. Silton tells Lovegrove they'll have to have something done about this vault, as they can't have chaps with hairpins wandering in and out. It means fitting a new safe, but they could do worse than going back to the old one, as at least that took Parker two and a half hours to open.

Penelope and Parker drive home. Penelope says there's one thing about this business that bothers her still. Why did that old safe take him so long to open, when the new one only took him seconds? Parker explains that the first time, they had an audience, and there's only one rule that must never be broken: never disappoint your public. He apologizes for the misunderstanding earlier, as it wasn't anything to do with Light Fingered Fred after all.

Back at the bank, Fred makes his explosive entrance into the bank. But when he gets in, he sees the vault is still open, and sees another wall has been blown apart already. He says that people call this place burglar-proof, but he thinks they'd do better to use his kid's piggy bank!