This week's Miss Fisher's Murder Mysteries cold open begins at Farrell's Circus, as performers ready for the show. But when the lovely Miss Amelia Parkes (Victoria Thaine) steps forward to enter The Amazing Vanishing Act box for magician Mr. Sheridan (Greg Stone), there is a body inside. It's his other assistant, Miss Christopher (Moira Finucane), filled with knives and covered with a snake. The tragedy drives Samson (Aaron Jeffery), the strongman of the cast, to go call upon Miss Fisher. He's hoping to hire her to look into the death of Miss Christopher, as the police are not interested in solving it. But Phryne is reluctant. The circus was where she and Jane used to go as children, and it's where her sister disappeared.
Collins: I've been shot, sir!
Elsie: Don't turn it into a three-act play.
Miss Fisher tries to get Jack involved, but the case is assigned to Snr Sgt Grossmith (Joel Tobeck). Jack appoints Collins to help Grossmith with the case, but that's all he can do. Despite Phryne's reluctance, it's time to run away and join the circus. Samson brings her in and introduces her to the ringmaster, Mr. Jones (John Wood), as a replacement, under the name of Fern. The timing is perfect because Amelia is refusing to go back on stage. Fern is hired right away, despite Jones wondering where he's seen her before.
Miss Christopher was a desperately unhappy woman, abused and traumatized from a young age for her transgender status. Samson also mentions she was amain attraction at the "Peep Show" for it, which she hated, and had threatened to quit. The snake charmer, Doreen (Maude Davey), was jealous of Miss Christopher's relationship with Sheridan, telling Fern to "keep her hands to herself" around him. Sheridan gets around, Parkes was also one of his girls. Christopher trusted Amelia, telling her she was saving money for gender reassignment surgery. But when Parkes caught Sheridan and Miss Christopher together, she'd had a jealous fit.
Meanwhile, Collins is having a devil of a time with Grossmith, who has no interest in the circus case. He also seems to be oddly in league with a pair of thugs, the Roy Boys, who they come across trying to rape an older lady named Elise Tizzard (Gillian Jones). (Grossmith calls her "Lizard.") Grossmith takes Collins out drinking, which horrifies Robinson. But Collins is trying hard to impress, digging up one of the circus people had a prior arrest for murder. It's Miss Parkes, who willingly steps up and puts her wrists out before Collins can even finish saying she's under arrest.
Elsie Tizzard is a known personality to Robinson. Her son, Matty, committed a bank robbery, and is in Parkreach Prison, though the money is still missing. She insists the Roy Boys are trying to rob her of it. Robinson has Collins escort her home, where they find her place is being tossed. Collins tries to shoot at the assailant but ends up shooting himself in the leg, as well as covered in grease. His leg is grazed, but it's enough to get Dot down to the station. Elsie says it was Matty, but Robinson insists he's locked up. Elsie ends up in Amelia's cell.
Parkes' murder charge stemmed from her husband's death during a trapeze act when she failed to catch him. But doctors discovered she had gone into an epileptic fit, so she was acquitted. Amelia tells Fisher she hasn't been taking her meds and doesn't remember what happened after catching Sheridan with Christopher. Fisher fills Jack in on the other suspects, while he reveals Christopher was strangled. The props were added afterward, as a warning. Fisher snoops around Sheridan's tent, keeping a sharp eye on Jones, Doreen, and her new squeeze, a stuntman who never takes off his white greasepaint (Brendan McCallum). In between, she performs as Fern, with Sheridan throwing knives at her. When the last one nearly goes through her face, he practically collapses with apologies. Sheridan is terrified of something, and Fisher thinks the warning was for him.
Fisher has Samson break into Jones' strongbox to check the circus files. Inside there's medicine and a giant pile of money, Matty's robbery stash. Perplexed Robinson calls Parkreach only to learn Elsie was right. Matty isn't in jail. He's dead, killed in a fight with another inmate two weeks ago. Or did he? When Elsie, in her grief, shows Amelia a picture of her son, Parkes recognizes him immediately. He joined the circus two weeks ago as Matthais the Ghoul, and never takes off his greasepaint. Not even when robbing his mother's house, if the grease on Collins is any indication.
Grossmith's penchant for the Peep Show gets Fisher caught out when he sees her with Samson. He declares the case is solved, whipping out a bit of rope he claims to have found in Miss Parkes' tent. But Fisher and Robinson have already put together the medicine in Jones' box was an animal tranquilizer. It helped Matty appear dead after the fight, so that he could be sent to the cemetery. He paid Jones to help him escape via a trick coffin built by Sheridan. But Collins discovers Matty's opponent also "died" after the fight: Murdoch Foyle.
Robinson freezes when he hears that, and he and Collins race to the circus. But they don't reach Fisher in time to tell her. She learns it from Matty when she confronts him. He insists the fake death escape was Foyle's idea. He and Foyle were supposed to meet at the circus, but Foyle still hasn't shown. Then Grossmith shows up, marching Fisher off at gunpoint. He was in on the escape, killing Miss Christopher when she demanded more money to keep quiet. Samson catches wind of what's happening and knocks Matty out. He sneaks up on Grossmith, who tries to shoot him. But Jones grabs Grossmith, so the bullet only grazes Samson's shoulder. Collins and Robinson arrive as Fisher takes tGrossman out at the knees.
At least Elsie gets to see her son one last time before he goes back to lockup. Miss Parkes goes free. As for Foyle, Robinson does some legwork and discovers the plan went awry. Instead of going unclaimed to the trick coffin, Foyle's mother asked that the body be cremated, suggesting he was burned alive. Fisher's hope of answers to Jane's death has gone up in smoke, but at least Foyle will foil her no more.