The Bletchley Riddle

Colin brings Lizzie his tools to help her open the lock on her diary. The inside of his room is full of clocks, radios, and mechanical devices that Colin has been working on. Colin springs the lock with little effort. Lizzie thanks him and then rushes to Bletchley Park. Lizzie wonders if the diary can help her find Willa.

The Colonel’s secretary leads Jakob to the second floor of the mansion, where he will be onboarding the new mathematicians. He puts a code on the chalkboard and practices a short lesson about the Caesar shift code. A woman arrives in the doorway and solves his cypher. Her name is Beryl.

John arrives too, and they begin. Jakob explains the basics of cryptography and how technology affects it. He explains that code breakers are always working to keep just ahead of them. He introduces them to the new German code, which has no numeric system or clues in the language. The only logical explanation is that the Germans have some sort of cypher-generating machine. Jakob picks up the machine and places it on the desk. It’s an Enigma machine.

John and Beryl inspect the machine. It is essentially a clever way to turn one letter into another. The Colonel steps in and gestures to Jakob to continue. Despite having the machine, they are unable to read them because they don’t know how the German operator sets up his own machine; it’s a math problem. There are over 10,054,560 combinations of settings possible in the machine. There is an additional level of complexity on top of this. This leads to well over a billion combinations.

John and Jakob are intimidated by the complexity, but Beryl seems to take it in stride, joking that to check one combination a minute they’d need longer than the age of the universe.

Colin walks Lizzie to the Park. They meet the man in the trench coat as they head out. Colin then gives her a tour of the village. Lizzie notices Colin’s mild limp and asks about it. He explains that he broke his leg, and it didn’t heal correctly.

At the Park, a guard asks Lizzie for a pass, and she says she doesn’t have one and that she was instructed to turn up to see Commander Bradley. The sentry tells her to wait while he makes a call. There’s a lot of security, and Lizzie asks why. Colin doesn’t know. Lizzie asks him to get her a magnifying glass and somewhere to hide.

The Colonel says they could have broken the Enigma code early in the war. They suspect now that it is unbreakable, but only if used perfectly: If an operator makes a mistake, they can exploit that. The potential for an operator making a mistake gives them hope, but they need another piece of the puzzle.

The guard lets Lizzie into the Park. She approaches the manor, impressed by the noise and activity. She spots a man in an apricot bowtie on the lawn and asks where she can find Commander Bradley.

Upstairs in the mansion, she finds Bradley’s office. He isn’t there, and she uses the opportunity to use his phone to call the US Embassy for Olivia, an embassy clerk who seems to be in London. Commander Bradley arrives. He says that she will be a messenger for him. She objects, but the commander says it’s an order.

A small girl called Marion appears, and Bradley tells her to show Lizzie about the property. Lizzie is then given a pass.

Marion tells Lizzie that she impressed Bradley. Marion’s parents were Jewish and fled from Vienna before the war, and her sister was sent to Florida. Lizzie says that she’ll introduce Marion to Colin, citing the importance of friends at this time.

Lizzie asks Marion about the phones in the mansion, if the exchanges are anonymous. Marion claps her hands over her ears and says they shouldn’t be talking about such things.

Jakob is swimming in a pond by the town’s brickworks. Swimming reminds him of Willa, who would swim in any weather. He recalls his bond with his mother and their shared love of spy craft.

Jarvis, the MI5 agent, is waiting for him by the shore. He walks with him to town and asks about Willa. He wants to know what happened to her, saying she vanished in Poland. Jakob says she’s dead. Jarvis continues to ask Jakob about Willa’s assignment in Poland.

Jakob recalls her arriving at his room in the Mutton before her disappearance and leaving him with newspaper clippings of recipes, which had a coded message hidden in them. Jarvis wonders why Willa didn’t leave with the embassy staff and suggests that she’s a traitor. Jakob is horrified at this thought. Jarvis says if Jakob or Lizzie obstruct his investigation in any way, he’ll charge them with treason. Jakob continues into town, unsettled.

Lizzie is tired after a long day running messages. She invited Marion to the pub for dinner. When Lizzie arrives at the pub, everyone is crowded around the radio, listening to one of Churchill’s famous speeches. Jakob looks shaken.

Jakob is out with the codebreakers running local defense drills in the woods along with Colin and few others from the village. His life has been in disarray since Lizzie arrived. Jarvis seems to have gone, though.

After training, they head back to the pigeon loft. Nigel is suspicious of Alan Turing and says he’s going to find out what he’s up to.

Lizzie hasn’t been able to make another call to Olivia and instead has been poring over Willa’s book. However, it is written in code. She has sent a letter to Willa’s housekeeper, Viola, in Wales, and told Marion about her plans. She can’t tell Jakob because he’s very distant and dismissive. Lizzie has had very unpleasant dreams of her Gran coming to get her.

Later, Lizzie is on the train platform with Colin. She has taken some money from Jakob to get a train to London, where she hopes to contact Olivia. Colin wants to come for the chance of seeing some spitfires (fighter planes) in the air. Marion arrives with a letter from Viola. The train arrives. Marion stays behind to keep Jakob off their trail. Lizzie and Colin board the train.

Jakob is at the newspaper stand. The headlines talk about the first German air raids. He spots another headline that says that a US Embassy aide has been arrested as a suspected spy. In the photo with the story, Jakob spots Jarvis. Nigel arrives and says that Turing is up to something and calls on Jakob to help spy on him.

Lizzie and Colin are on the train. She reads her letter from Viola. Viola shares that she received a call from Lizzie’s grandmother in America: Fleetwood is returning to London to find Lizzie and bring her back to America by force. As they approach London, she realizes that the city is prepared for war.

Jakob is up a tree with Nigel watching out for Alan Turing. Alan is pushing a pram loaded with something heavy and carrying a shovel. He digs a hole and starts placing heavy objects into it and burying them. Jakob and Nigel wait a few minutes before trying to dig up what Alan buried. It’s a brick of pure silver. They cycle back to Bletchley. Nigel wants to tell the police, but Jakob says to wait a couple of days.

The train arrives in London. They head for the American Embassy and ask to see Olivia. She arrives and brings them to the garden across the street. Olivia tells Lizzie about the German invasion in Warsaw, but Lizzie insists that Willa’s not dead.

Olivia reveals that the American Embassy staff are going to be attending a party to watch a film. Lizzie thinks that she’ll attend to interrogate the ambassador. Oliva then reveals that Mr. Fleetwood was at the embassy just before Lizzie and is actually across the road at a café.