The fifth episode of Miss Fisher's Murder Mysteries' cold open begins with a woman who better call Saul. He's fallen into an epileptic fit in the bookshop. As the woman, Miss Leigh (Kat Stewart), tells him to relax into it, the scene cuts away to an auction already in progress, run by Melbourne's Kadimah student association. A man in the front row, Simon (Tim Draxl), one of the few without a kippah, is concerned Saul hasn't made it back, as Miss Fisher steps in and outbids the room for the painting in question. But her win is muted when Ben Abrahams (Brian Lipson) steps into the room and beings arguing that this whole enterprise is shameful. The auctioneer, Yossi Stein (Adam Schmerl), insists this fundraiser is for the good of their people.
Miss Fisher: It was poison. I'll bet my hat on it.
Ben's not having it and takes both the painting and Simon (who is his son, it turns out) home. Phryne, having won it, follows them out, only to learn Simon stole it. As she angles to convince Ben to sell her the painting privately (it's an early Margaret Preston), Leigh runs out. Saul Michaels is dead... and he didn't have epilepsy. Fisher orders Simon to call Jack Robinson.
Jack sizes up the scene, but as usual, Fisher sees the crucial detail — a teacup handle under the body. The rest of the teacup is in the trash, and the teapot's in the cupboard, still warm. Collins learns Saul was apprenticed to Ben's brother, Chaim (Adrian Mulraney), a cobbler, whose shop is also in this same building. Leigh tries to act as if nothing's happened, as Chaim talks up the young man. But Ben's not having it. Saul, he says, was a Zionist, who thought all life's problems would disappear if all Jews simply packed up and went home to Israel.
Back at Miss Fisher's house, Cec's engaged! Also, Simon and Ben have arrived, hoping to hire Miss Fisher. Leigh has been charged with murder, and Simon's willing to give Phryne the Preston to prove otherwise. Fisher agrees, heads to the station to question Leigh, and then breaks into the bookshop to do some sleuthing for the book Saul was returning. But someone else does the same, going directly for the volume in question. Fisher gives chase across the rooftops, knifing him in the shoulder after he shoots at her. He drops the book, letting Fisher head home with it.
Simon arrives with a bouquet of flowers and shows Fisher Jewish immigrants hid valuable papers in the spines. This one has a piece of the Kabbalah. The bookshop was where the Zionists met; Leigh was covering for them. He takes her to to the shivah being held for Saul, where Yossi is extremely rude, trying to take back the Kabbalah page in the guise of "translation," but Fisher refuses. Instead, she and Simon meet Chaim to examine Saul's workbench and rooms. FFisher does find a copy of the Kabbalah where the piece of the page came from, and proof Leigh was in Saul's bedroom. Leigh admits she and Saul were in love. But he had a wife, back in Poland, who was planning to meet him in Israel, which is why she can't be emotional over his death.
Saul believed he had just found a way to get rich, so he and the others could go to the Middle East. The Kabbalah page seems to back the idea up. Jack recognizes the symbols for lead and gold on it. Also, the tea wasn't the poison agent. It was a paper cut, which turned black. Simon reveals Ben can translate the old Hebrew written on the page, though his father dismisses the Kabbalah as mystical nonsense. "The invisible will become visible only through flames." Simon is intrigued by the mystery, and by Phryne, but before she can bed him, Yossi breaks into her house. He foolishly believes Saul could turn lead into gold. But he doesn't know the formula, and he wasn't the one who broke into the bookshop. His shoulder is uninjured.
The next day, Yossi turns up dead, also with blackened fingers, just as Jack figures out the message: a formula written in ink that only visible when heated. Dr. Mac comes in to consult, noting to Dot poisons are everywhere, including the bouquet on the mantle, the same flowers Simon brought over. She follows Saul's formula to see what he made, which turns out to have been for artificial rubber. Not gold, but in these modern times? Worth its weight in it.
Dot's been sleuthing too, turning up the name of the other bookshop patron, one Archie Davies (Don Bridges). Bert and Cec are assigned to track him down, but their spat over Cec's engagement means they're going it alone until Bert nearly gets beaten up, and Cec saves him. Archie is discovered on sleeping on a bench wearing rags and very fine shoes. He was asked to return a book, which turns out to have been Saul's favorite book of Yiddish theater songs, including the song "Raisins and Almonds." It was poisoned, both page and spine, a powder ground from the flowers in Ben's garden.
As Fisher arrives at Ben's house, Chaim runs up. Simon has been kidnapped. Dot calls Robinson while Fisher takes the Abrahams to "follow the kidnappers' instructions." But she's already put it together — Chaim, the cobbler, paid Archie in a new pair of shoes. He's also got an injured shoulder. It turns out, he was the one who came up with the artificial rubber idea, but Saul stole it for the cause. He was tired of being treated as a second-class citizen, made to give up his hopes and dreams for the family. This was his revenge.
When Jack arrives, Chaim attempts suicide with Fisher's gun. But that's how we learn it's not loaded. Jack once again is impressed by Phryne's ability to get her man, even if she hasn't gotten him. Not yet, anyway.