This week's Miss Scarlet & The Duke kicks off a mere day or so after the events of "Deeds Not Words" and Eliza's successful bringing down of a bomb plot to take out Parliament. It's also the moment when she realizes that Duke is no help to her. When the story reaches the papers, he's the one taking all the credit for her work, driving home the accusation that she's just letting men use her. It's a blow to Rupert too, who was hoping his investment might pay dividends or at least upset his mother.
Eliza is so frustrated she blows off the kindly Herr Hildegard (Richard Evans) instead of her usual impatiently polite stance. But the wily old undertaker has an ace up his sleeve, mentioning a case that's right up her alley.
Eliza: Oh, you're facing prejudice in your chosen career? What must that be like?
It's a case that's been on Duke's desk for a while now, one he considers not worth pursuing. Mr. James Henderson (Hugh O'Conor) is a photographer who specializes in memorial portraiture, known as "memento mori." But Henderson's problem isn't a client; it's with the dead. His late wife, Catherine, is sending him threatening messages and haunting photographs with her ghost overlayed on them from the grave, ever since he got engaged to Amelia (Roisin Murphy). Amelia is James' assistant and governess to his young daughter Violet (Amelie Metcalfe), who helped him through Catherine's prolonged illness. She also believes this is punishment, as they fell in love and have been sleeping together since before Catherine passed.
Catherine knew about the affair, and her final words to Amelia threatened to haunt them forever. Furthermore, Amelia's mother, Edith (Marion O'Dwyer), is a medium and agrees the dead say Amelia's best bet is the break off the engagement.
Eliza thinks this is all nonsense, but Edith might not be the source. The photograph's "ghosts" are made from a manipulation only a professional can accomplish. Moreover, Edith seems to know a great deal about Eliza's father, Henry, reciting a moment viewers saw in flashbacks earlier in the season, when Eliza and Henry dissected a frog together.
But Eliza seems never to get to have a case to herself. With his bomb plot fame, Duke now has a reporter nipping at his heels, looking for a topic to write about in The Illustrated Police News. Though it's not the London Post, it is the most widely read inside the industry and by the Home Secretary. Superintendent Stirling wants Duke to give them a feature article, where Stirling himself gets mentioned and credited a lot, of course. When Duke balks, he's reminded of that promotion hanging in the balance and immediately sets to impressing the reporter, Bunce (Kevin Eldon).
Bunce is bored by Duke's "impressive" cases. When he learns of this "memento mori" case, he declares that to be the perfect subject for their readers, sending Duke suddenly parachuting into the middle of Eliza's work. It's useful in that he arrives just as Eliza is running into roadblocks a police inspector can cut right through. But it's also a massive problem because now Duke is trying to hide from her from knowing there's a journalist involved in writing up the case while also shielding him from discovering Eliza's existence.
With Duke's ability to get into Edith's correspondence and Eliza's search of her rooms, they piece together Edith is a fraud. All her information comes from funeral homes and undertakers who need money. In Henderson's case, it's Ruth, the maid, who Edith regularly pays to keep her in business, and more recently, to engineer her daughter into breaking off the engagement. Ruth is also the frog story source, which Herr Hildegard regaled James with at dinner recently.
Unfortunately, just as Eliza beings to mistake Duke for an actual partner, his underling, Frank, makes short work of keeping Eliza in the dark about Mr. Potts, shooting his mouth off about the article without realizing she's in earshot. Duke attempts to smooth things over, but Eliza is not having it. Duke tries to explain he needs this for promotion; as a civilian, he's hit a glass ceiling. The police force is an ex-officer's boy's club; Duke needs a leg up. He's met with zero sympathies. After all, if there's one thing Eliza knows, it's being shut out of boy's clubs, all of them. She tells him to buzz off.
Alone again, Eliza discovers her proof Edith's mother was a fraud ended the engagement after all, since Amelia now feels James can't trust her. As Eliza heads downstairs she discovers Violet playing at memento mori photography with her dolls, imitating her father. But Violet's also imitating her mother, who was James' assistant once upon a time. Catherine knew a lot about photography, including how to manipulate photos. In the girl's chattering to herself, Eliza realizes it's her who is sending these photos from "beyond the grave." Catherine's final directive to her daughter was to play a "game" of delivering the messages, innocent of the harm she's causing.
It's an ending that requires therapy and big hearts, not jail time, and James forgives his daughter, reuniting their little family with Amelia as well. Eliza is delighted she solved the case, but Rupert isn't listening to her recap. He's distracted by his decision to court Herr Hildegard's daughter Tilly (Amy McAllister). He's also worried Eliza might disapprove. Instead, Eliza laughs, calming his fears. As Parker struggles to court Tilly properly the next day, it seems an assurance to viewers the Hildegards are an official fixture in the series.
As for Duke, all his work, all his fawning over Stirling and cutting out Eliza has been for naught. Stirling was never going to give him the promotion, which he learns to his horror. Moreover, Stirling has little respect for Duke, sneering at Henry's memory and Eliza playing detective, which infuriates Duke further. Realizing that he's screwing over the only partner he has in this business, Duke does the right thing. He grabs Bunce before the article goes to press and tells him the truth. The next morning, Eliza is the headline: "Death & The Maiden: Female Detective Cracks Case of Ghostly Terror." It might not make up for all Duke's done. But it's the first step in rehabilitating him, which will hopefully continue from here on out.