Plot

Metal detectorist Errol Prowse is killed after finding a cache of valuable coins. Locals believe it is Long Ben's treasure and anybody who finds it will be cursed. Museum curator Tal Greening tells Jane they are fake but Errrol's granddaughter Amelia claims she believes his find was real but fakes were substituted after he was murdered. Errol was not popular with other treasure hunters, two of whom shared a secret but Tal and even Amelia are also under suspicion—don @ minifie-1

A man is out by the seaside cliffs with a metal detector. He is with a group of treasure hunters. Just then he finds something and digs it up. It appears to be an old Spanish doubloon. The others all smile.

At the pub, the group is there having beers. The man tells everyone to keep the find quiet. All finds in the group are divided equally, and the man calls the coroner's office, as they are responsible for adjudicating found treasure.

The man takes the found coins home in a box, has a drink, and sits in his chair with a rifle as the storm rages outside. Someone is banging on the door. The man shivers in fear and yells out.

The next morning the man is in his chair, dead. There is a hole broken through his window. CID is taking crime scene photos.

The coins are believed to be part of the treasure of Long Ben, a local pirate legend who's treasure is said to be cursed.

Clint and Jane are heading to the man's house to look into the coins. As they arrive, they see the police there. Davey is impressed she's there so soon. She doesn't know the man is dead.

In the house, Jane examines the hole in the window, which Davey says was from the inside. The man, Errol Prouse, called 999 that night saying he was in danger, but by the time police got there, he was already dead. Davey thinks he scared himself into a heart attack.

The man's granddaughter Amelia lives with him, but isn't there. Her parents died in a car accident and he's her only remaining relative. Davey and Jane spar about who has authority over the coins -- Davey says it's evidence, but Jane points out treasure is her department.

Amelia comes home and is devastated to see her grandfather dead. She was in Exeter last night with friends for her birthday. She doesn't know about the coins he found. She knows he goes out with the Lighthaven Treasure Hunters, the group he was out searching with. One of them is lingering by the scene.

At Jane's office, they play back Errol's 999 call, frantically yelling about "he's coming for me," and referring to Long Ben.

Errol's house was locked from the inside, so no one could have got in to harm him. Amelia's alibi checks out, so it's a mystery how he died unless it was natural causes. Also, no one took the coins. Jane still suspects foul play. She goes to have the coins assessed at the Lighthaven Museum. It turns out one of the employees at the museum is one of the treasure hunters.

Jane meets Professor Greening at the museum, and shows him the coins. He goes to examine them in his lab.

Davey is questioning the treasure hunter, Debs, at the museum. She says after they left the pub, they walked Errol home, then she went home. Errol was in a grumpy mood, but he always is. They were the only ones to know about the coins.

Greening has bad news, the coins are fake. Jane mentions some thought it was Long Ben's treasure. Greening says Long Ben wasn't a myth. He shows her a Long Ben exhibit in the museum. He shows her an authentic doubloon. The person who found it died soon after and talk started of a curse, which they joke about. Greening asks to take her to lunch.

Debs says the club has dwindled due to Errol scaring people off. But she has stuck with them in case they find something, and the smaller the group, the bigger the cut. Jane enters the gift shop and buys a bracelet for Beth, with red beads and a skull and crossbones.

Jane noticed Debs had expensive shoes, and wonders how she can afford them with that job. Davey suggests a well off boyfriend. Jane tells him the professor identified the coins as fakes.

Amelia is in Jane's office. She insists the coins can't be fake, as her father would know the difference. She insists someone must have swapped in fakes. She desperate as her grandfather left her with nothing and the home is underwater.

Jane decides to look into Amelia's theory. Davey and Jane run into Ray, one of the treasure hunters. His story is much the same as Debs'. Jane wonders if he knows for sure everyone went home; Ray says it was very late. Jane asks if its possible someone stayed behind and swapped the found coins with fakes. Ray says it's impossible as all of them were watching the box. He can't confirm when he got home, but when Jane suggests double checking, Ray admits he stopped off to see someone: Anthony, another of the treasure hunters.

At the pub, Davey and Jane talk to Anthony, who confirms they were together all night until early morning. He's only still in the group because of Ray, because he can't stand Errol.

Mick comes over and orders Anthony out of the bar due to his contact with Long Ben's treasure. His customers are superstitious types and they'll stay away to avoid the curse. Anthony leaves the pub, and calls someone, saying he needs to see them.

Jane theorizes that Errol's death was caused by something that happened before he got home. They go to the mortuary to read the post-mortem, which indicates poison as a likely cause of death. He could have been poisoned in the pub, or someone could have visited him at home, poisoned him, then left.

Greening and Jane sit by the beach. Jane tells him Amelia's theory about the coins being swapped. Greening is dubious. He knew Errol, but didn't like him. Greening is concerned about the museum's future, as there's been budget cuts.

Debs is crying. She opens up her handkerchief, and she has one of the found coins in it.

Davey calls Jane to the station. Debs is there, and wants protection from Long Ben. Debs admits she kept one of the coins, without putting it in with the group's. She's lost her job at the gift shop and thinks she's now cursed. She gives the coin to Jane, but Jane tells her the coins aren't even real.

Davey and Jane pull up to Ray and Anthony arguing. A witness near Errol's home saw Ray's van near the house last night. Anthony takes the blame. Anthony was drunk and got paranoid so they went to demand their share from Errol, and Errol shot at them. They heard sirens and left. Ray went back in the morning to talk to Errol, but saw the police; he was the one lingering.

Davey argues Ray has motive and opportunity, but Jane is dubious, and poison implies premeditation, not impulse.

Jane has Clint looking into places that sell fake doubloons, to see if any were bought in the area. Jane compares the coin from Debs with the one from Errol's box; she then suddenly gets up and leaves.

Jane goes to the museum. She shows Greening the coin that Debs kept. He has to run and take care of something quickly. While he's away, Jane looks at the Long Ben display, and notices an exhibit description that mentions coins, but there are no coins there. She has a realization, and leaves.

Jane goes to Davey. Davey has found out that Errol called Professor Greening from the pub. Davey theorizes that when Greening learned about the found coins, he went to Errol's to steal them, poison him, and swap the coins with fakes. Jane realizes Greening wouldn't have done that without confirming they were real first, and Jane realizes she was his opportunity. The coins she gave him were real, and the ones he gave her back were fakes. Davey mentions they haven't identified what poisoned Errol.

Mick looks at the bracelet that Jane bought for Beth at the museum store. He tells Jane that he sold those bracelets to the gift shop, but later learned the beads are made from poisonous beans. Jane has a realization.

Greening is in his office. He grabs a key and opens a shelf to get a box. The real coins are in there, and he counts and examines them. Jane calls. She tells him the real treasure has been found and the person who stole them is being arrested. Greening stashes the coins and runs out of the museum to find Davey and Jane. Jane remarks that antiques collectors would pay a lot for those coins. Greening argues that the museum is running out of money and in danger of shutting down, and selling the coins could have kept things going. Davey arrests Greening.

At the station, Davey probes Greening about poisoning Errol, but he claims ignorance. He admits to swapping the coins but not to killing Errol. Greening points out that plenty of people work at the museum and had the same access to the poison beans.

Davey and Jane arrive at the gift shop to find Debs packing up her things. They confront her about the poison bracelets. She says she found out from Mick about them and has been trying to give them all back. But the shop records show that Debs bought one for herself. Debs says she bought it because Errol asked for it and used her employee discount. He got it as a present for someone else.

Jane and Davey visit Amelia. Jane tells her the treasure has been found. Davey asks about her bracelet, which is a health hazard, but she denies having a bracelet. Davey found the remains of it in her trash bins. She says she threw it away, but Jane is incredulous that she'd discard a gift from her late grandfather. Jane accuses her of poisoning Errol with the beans' poison. She denies it saying her grandfather was a wonderful sweet man, which Jane scoffs at.

Jane and Davey looked into the accident that killed Amelia's parents. They didn't just die in a car accident, but it was an accident that Errol caused while driving drunk, and fled the scene leaving Amelia behind with her dying parents. She's resented living with the man who killed her parents since then. Amelia did everything for her grandfather, and cooked him breakfast the prior morning. The poison takes time to take effect, so that would fit the time the poison could have been given.

Amelia knew her grandfather was leaving her nothing. She was going to sell the cheap bracelet, but then found out about the poison, and it gave her the idea. Davey arrests her.

The next day, Jane heads to coroner's court, seeing Anthony, Ray, and Debs heading in for the treasure verdict. Jane's verdict for the death of Errol Prowse: Unlawful Killing.