Knocker returns to the garage, and finds the weapon Bowler Hat Man used to injure him.
Bobby scribbles a note and hides it under the passenger sun visor in the Nicholsons’ car.
At lunch Dr Nicholson explains his reasoning that he doesn’t think Frankie’s crash was real. Benjamin, who witnessed it, said the car was facing uphill towards Staverley, in which case he’d have seen it just before, but he hadn’t. And for the doctor (George) to witness the crash, his car would have to have been going in the opposite direction. So if his claim is true, the doctor must have turned his car round before coming to help the injured Frankie. Roger defends her.
Frankie questions Moira about living at The Grange. Outside, she tells Bobby she believes her husband is going to kill her, as he loves Sylvia. She says she had one chance to escape and didn’t take it. She did know Alan Carstairs, she admits — “he was a protector, like you.”
In their car, she finds Bobby’s note: “I’m here.”
Frankie and Roger go for their drive. Roger admits he doesn’t believe the crash story either and accuses Frankie of changing the side of her forehead her plaster is on. She hasn’t, but she has to check it to make sure. He removes it and there’s nothing underneath. She hits him, then agrees to tell him how she crashed the car without hurting herself. But first she demands to know about the photo substituted in Carstairs’ pocket after he died. Roger claims he didn’t substitute a photo; actually he just tore the picture of Moira up, after it fell from Carstairs’ pocket as his body was being removed. This was to protect Moira, a married woman, from being shamed by the press. Roger claims he’s never heard of Mrs Cayman. Frankie confesses she thought he’d pushed Carstairs off the cliff. As Roger claims he didn’t substitute a photo, only remove one, they wonder if the second photo — of a young Amelia Cayman — was already on the body.
Bobby is in the Merroway Court kitchen helping Henry and Sylvia’s young son Tommy write his homework. He’s using an identical fountain pen to the one found in Alan Carstair’s pocket, and Tommy tells him Mr Savage gave it to him when he visited earlier that year. Frankie and Roger go back to the house. Frankie has tea with Sylvia and they hear a gunshot. Henry, locked in his study, has shot himself. Dr Nicholson appears.
Frankie and Bobby have dinner at the Anglers Arms and discuss the death; Bobby isn’t convinced it’s suicide. He reminds her that Moira said Dr Nicholson would kill her and Henry. Bobby sees a picture on the pub wall of Alan Carstairs and Mr Savage together.
Frankie goes to The Grange to see Moira Nicholson; Bowler Hat Man opens the door. Bobby, still pretending to be her chauffeur, walks round the grounds. Dr Nicholson tells Frankie that Moira has gone to London. He calls her Lady Frances, and she asks him how he knows about her title, as she hasn’t told anyone locally. She leaves, but downstairs Bobby discovers someone has cut the magneto wires on her car. They freewheel down to where they can check it out of sight of prying eyes.
Henry’s funeral takes place. Frankie introduces Bobby to Roger afterwards, admitting that Bobby is her friend, not her chauffeur. Roger recognises him as the caddy who found the body. Bowler Hat Man is also there; Bobby and Frankie recognise him, Bobby from inquest and Frankie from The Grange.
Frankie goes to the Naval & Military Club in London to try to reclaim Alan Carstairs’ belongings, sent there by the landlord at the Anglers Arms — she pretends to be Carstairs’ niece. She looks through all his letters; there are many from John Savage with mentions of how much he loves Rose Templeton.
She then goes to dinner with her father’s solicitor Mr Bragge, questioning him about Savage’s will. Bragge is very forthcoming: Savage met Mrs Rose Templeton on a boat trip and they fell in love. He then developed an obsessional belief that he had cancer, and killed himself with an overdose of chloral hydrate. Two days before his death, he had left £140,000 to Rose Templeton. Savage had no other relatives to query it.
Bobby goes to Dr Nicholson’s health clinic, The Grange, where he sees the Caymans. Two orderlies grab him and he’s drugged by Bowler Hat Man.
Frankie finds a note in her room at the club from Bobby, with the address Mill House, Chipping Somerton (the address matching the house details Bobby found in Roger’s room at Merroway Court), asking her to come quickly.
She drives there, another car following her, though she gives them the slip. Entering the house, she is overcome and drugged by Bowler Hat Man, coming round tied up in a room with Bobby. She’s immediately sick.
Discussing the case, neither can understand why the Caymans are still around when they’ve not got so much money (Bobby and Frankie believe the Caymans to be behind the plot). Bobby laughs that they clearly thought he and Frankie understood the “Why didn’t they ask Evans?” line, and that’s why the two need to be disposed of, before the Caymans can escape abroad with their loot. Yet neither Bobby nor Frankie are any the wiser re Evans’ identity.
Bowler Hat Man comes in and makes Bobby read loud an agreement to “experimental neurological procedures”. Dr Nicholson appears in the doorway. Frankie tries to bluff Nicholson that she’s told Mr Bragge about everything, including Evans, who she refers to as “him”. Nicholson says it’s a bluff and leaves, saluting “Bobby Jones” as he goes.
Bobby tells her that wasn’t Nicholson but Roger Bassington-ffrench. Frankie realises he’s right: the man in the doorway called her Miss Derwent, while Nicholson always called her Lady Frances. (Presumably the salute was a Navy one.)
Knocker bursts through the window to rescue them. Bowler Hat Man comes in with Knocker’s knife, taken from him during the garage attack. Knocker has the other man’s cosh from the same assault and suggests they swap. The two fight, with Bobby and Frankie unable to help. Eventually Knocker stabs Bowler Hat Man to death, and frees the two from handcuffs. It turns out it was Knocker following Frankie down in the car, as Bobby had asked him to look after her. Knocker is later released without charge, thanks to Mr Bragge, who acts as his lawyer.
The next day Bobby and Frankie go to see Mrs Pratt: Mrs Templeton’s cook, one of the witnesses of John Savage’s will. She hadn’t worked at Mill House very long when she and Alfred, the aged gardener from the first scene of episode 1, were asked to witness the will — despite Gladys the parlourmaid being in the house. The day after the will-signing, the 89 year old gardener was conveniently found dead.
After their visit, Frankie asks Bobby why they didn’t ask the parlourmaid to witness the will instead of Alfred, when she was in the house already… Bobby already has an answer: he had stayed behind and found out from Mrs Pratt that the parlourmaid was called Evans. So… Why didn’t they ask Evans?
Bobby does some investigating, and finds out that Gladys has recently married and returned to her birthplace in Wales. She is now Mrs Roberts, and her address is The Vicarage, Marchbolt… where she is the housekeeper for Bobby’s dad.
Knocker lends Bobby and Frankie a car and they begin the long drive back to Marchbolt. En route, Frankie remembers her mother’s words, that the maid in a house knows everything. Frankie realises that only the parlourmaid — who unlike the cook and gardener would see all the comings and goings of the house — would have realised the ill man in bed was not actually John Savage, whom she had seen visiting before.
Frankie and Bobby spot a distressed-looking Moira Nicholson in Marchbolt, and stop to talk to her. The three of them go for tea. She says someone followed her off the train to London, and then claims he’s outside. The other two look out, as Moira declares the person to be Roger, and that he’s here to see someone else. Frankie notices Moira is putting something in their tea though, and pours it into a glass bottle, saying she will have it tested and it will turn out to be chloral hydrate. She calls Moria “Rose Templeton”, and in return Rose calls her an “arrogant entitled little bitch”. Frankie slaps her, then sends Bobby off at a run to find Gladys Evans/Roberts.She is in the vicarage talking to Roger — Bobby runs in and fights him, while Gladys bashes Roger over the head with a vase.
In the police cells, Frankie and Bobby get the whole story from Roger. Moira met John Savage on the boat crossing from New York; it was Roger who signed Savage’s will. He’s admiring of Moira, who he says has an instinct for crime. It was Moira who found a Dutchman called Mr Angel (Bowler Hat Man) to push Carstairs over the cliff. She also found the Caymans, giving them a cut for their part in the scam. Angel also killed Dr Thomas after he began to get too involved. Roger and Henry had always hated each other, with Roger feeling his brother was wasting his money “on misery” (beyond even what he spent on morphia). Roger killed Henry, but waited until Frankie was there, considering her a more plausible witness than Sylvia. Roger used a crow-scarer hidden in the chimney months ago to distract them on the timing, so the “gunshot” they heard was that. Henry was already dead by then.
And Dr Nicholson? He is innocent of all accusations, apart from being dull.
Outside, Bobby proposes to Frankie, using a washer from the magneto housing as a temporary ring.
The two are married in the local church by Bobby’s father Reverend Jones, with Frankie in a cream trouser suit and hat. They drive off in the Marcham family Lagonda.