In the 1920s, a daring rescue unfolds when Phryne Fisher helps free a young Bedouin girl named Shirin Abbas from an unjust imprisonment in Jerusalem, only to face a momentary suspicion that she may have died in the process. Shirin is reunited with her uncle, [Sheikh Kahlil Abbas], and the pair heads to England, where a memorial is being held at Lofthouse Manor for the woman who inspired so many of their friends. Among the mourners are Lord Lofthouse and Lady Eleanor Lofthouse, who welcome the visitors with warmth and ceremony. Also arriving is Detective Inspector Jack Robinson, who travels all the way from Australia to attend the service and lend his support as Miss Fisher unexpectedly makes a triumphant late entrance in a biplane, prompting the plan for a farewell Welcome Back Party to celebrate her return.
As the conversation shifts to Shirin’s past, she explains how a village was wiped out by a devastating sandstorm, leaving her as the sole survivor who was saved by a mysterious stranger. A letter from that stranger has ordered a meeting at All Saints’ Church at midnight, a plan Miss Fisher volunteers to attend on Shirin’s behalf—while inviting [Detective Inspector Jack Robinson] to accompany her for protection. When they reach the church, a British man named Wilson is suddenly shot by a shadowy assailant. Before he dies, Wilson passes an emerald amulet to Miss Fisher and asks that it be given to Shirin. In the chaos that follows, Miss Fisher and Robinson are arrested, and the authorities reveal that Wilson was a deserter who had once fought alongside Captain Templeton, who has already faced execution for desertion.
The plot thickens as the pair consult antiquities expert [Professor Linnaeus], who explains that the amulet bears the inscription “Crypt of Tears” and is connected to an ancient tomb tied to a legend about Alexander the Great’s last campaign. The legend speaks of a curse laid upon anyone who disturbs the tomb, a warning that proves disturbingly real when an unknown attacker tries to seize the amulet from Robinson but is repelled. Back at Lofthouse Manor the next morning, Miss Fisher learns that the Sheikh had signed a deal with Lord Lofthouse and Vincent 'Monty' Montague that would benefit the British Palestine Railways. After hearing from Shirin that British soldiers were responsible for the death of their family, Kahlil renounces the agreement in a pointed public denunciation during a party at the manor, only to be shot dead by the same unknown assailant that night.
Following this, DI Robinson visits Captain Templeton’s widow, who presents him with an astrolabe once owned by her husband. The widow’s story points to a tumultuous chain of events: Templeton’s execution, the supposed disturbance of the tomb, and a pregnant wife who went into labor under stress—though the baby did not survive. Meanwhile, Miss Fisher discovers a large emerald hidden in a pot in the Sheikh’s room, a finding Linnaeus confirms is connected to the amulet. The group—Robinson, Fisher, First Lieutenant Jonathon Lofthouse, and Shirin—travels to the Negev, guided by the astrolabe, and uncovers a tomb buried in honey, containing an ancient corpse believed to be Alexander’s desert bride who died from grief. A second corpse nearby bears Jonathon’s insignia, revealing a dark family secret.
Jonathon reveals his past: he had accompanied Templeton and Wilson to Shirin’s village years ago in search of the jewels. In the ensuing confrontation, Shirin’s mother—the tomb’s guardian—is killed in the ensuing struggle, and Jonathon’s complicity grows more sinister as he tries to shield himself from the consequences. The evidence points to Crippins, the Lofthouse family butler, as the mysterious protector who is standing in to safeguard Jonathon. Crippins emerges from the tomb’s shadows, attempting to seize the jewels, but Jonathon disarms him and restrains him as the tomb walls begin to collapse.
Back at Lofthouse Manor, Miss Fisher informs [Lord Lofthouse] of the truth about Jonathon. She then says farewell to Shirin, sharing a quiet moment that hints at the bonds forged across cultures and continents. A playful misdirection—mock shooting of a spider—gives way to a genuine, heartfelt exchange between Jack and Phryne: he confesses that marriage isn’t necessary for happiness, only that he needs her heart, and she insists she has already given it to him. The two share a tender night together, underscoring a union built on trust and adventure rather than convention.
The film closes with a mid-credits scene that hints at further intrigue: Phryne receives a letter announcing that her husband, whom she married to help him secure his kingdom, has been murdered, leaving the door open to further mysteries and the continuing allure of a life lived in pursuit of truth, justice, and a little danger.
