Shetland series 10 ramped things up in episode 5 this week, flipping the usual good cop/bad cop dynamic on its head as level-headed Tosh unleashed her inner fire-breather.
And the culprit behind her fury? Billy. Even the typically frosty DI Ruth Calder clocked Tosh “tearing everyone’s head off”. The outburst came after Tosh was crushed to learn that her “gold standard” policing idol, Sgt Billy McCabe, was nowhere near as spotless as she’d believed. Not even close.
In the penultimate episode, Tosh – dreading the truth – finally confronted Billy about Robert Tulloch’s past, and what she heard left her reeling.
Elsewhere, a guilt-stricken Ruth raced to track down whoever was behind Will Louden’s attack, edging the team closer to unmasking Eadie Tulloch’s killer. And yes, Ruth also edged a little closer to the victim’s son… perhaps more than strictly necessary.
***Warning: spoilers from Shetland series 10 episode 5 ahead***
What happened in Shetland series 10 episode 5?
Putting the pieces together, Tosh confronted Billy about Robert’s past in the police force, and the possibility that his mentor was corrupt. However, Billy angrily rejected the suggestion, leaving Tosh stunned. Reeling from his argument with Tosh, Billy did some digging of his own.
At the hospital, DI Ruth Calder waited anxiously for news about Will Louden. She knew he’d been clean for months, so his apparent overdose in Shetland episode 4 suggested foul play. Ruth decided to retrace Louden’s steps, which led her to a person of interest.
Meanwhile, a new suspect came to light when a fingerprint at Eadie’s house was identified. However, Calder and Tosh’s interrogation of this Lunniswick local took a surprising turn…
With a storm brewing, Ruth Calder considered an unlikely offer of hospitality, while Tosh was called out to the Lunniswick boatshed to hear a devastating confession…
What did Billy do?
All eyes were on Sgt Billy McCabe in episode 5 of Shetland. No longer the lovable, biscuit-offering, kindly copper of the past 12 years. In series 10, the shadow of suspicion has fallen on Billy, and we’ve seen him in a different light.
Long story short, he was best mates with bent copper Robert Tulloch, who was taking cash bribes to supplement his income. So why had Robert transferred Billy £10,000 in 2001? Was Billy corrupt, too? We finally found out the truth. Although he wasn’t crooked, he certainly wasn’t squeaky clean, either.
Billy insisted the money was a loan from Robert so he could put a deposit on a house. He told Tosh: “Morag and I weren’t long married. We needed a place, and I didn’t have the money. Robert offered.”
As Tosh told Billy he had a “duty to tell the police”, a surprisingly defensive Billy insisted: “Robert Tulloch was a decent man.” But he really wasn’t. And Billy later found this out himself after doing some of his own investigative work, and realising there was another side to his old mate.
Of course, Tosh was bereft that the colleague she’d looked up to could have made such a misstep. She later confided in Ruth: “If we find proof that Robert Tulloch was corrupt, we’ll have to report it. That means an investigation. That means they’ll look into all his finances. And, when they do, they will look at Billy. If he’s done anything illegal, then he’s finished.”
There was also the fact that Billy had hidden the bank statement from his colleagues, which made him look guilty. Even if he said he “panicked” because it looked suspicious. Which it did x 2.
Shetland series 10 episode 5: Billy hid the truth from the police
The truth eventually spilled out. And it left Tosh with a very difficult decision to make about her colleague Billy. After their heated exchange, and Billy’s volatile reaction to her gentle probing, Tosh spent the day like a bear with a sore head. But things were about to get worse when Billy asked her to meet up at Lunniswick boatshed where the shipwrecked boat Lintie was kept.
Once there, Billy told Tosh the whole truth. He talked about the storm that took the lives of Eadie and Robert’s son Craig, and Arthur and Ellie’s son Ally on the boat called the Lintie. The boys had gone out on the fishing boat the night before, and never came back. Billy explained: “The storm was supposed to hit 50 miles at sea. So when it diverted, none of us were ready.”
The boat subsequently washed up on the beach, but the bodies were never recovered. Billy searched the boat “trying to find something personal for the families to hold on to”. However, he found heroin on the boat instead, in fact “kilos of the bloody stuff”.
Now this is where it gets gnarly. Billy told Robert about the drugs, and the pair choose not to report it. He told a horrified Tosh: “Robert and Eadie had lost their son. Arthur and Ellie too. The whole village was mourning. What good would it have done to stain their memory?”
Will Tosh report Billy?
Fan favourite Tosh was crestfallen at the news that Billy hadn’t played by the rules. And we get it, we really do. But we kind of understand why Billy had stayed silent, too. Life isn’t black and white.
Of course, Tosh then suspected that Robert probably sold the drugs and made a stash of cash from it which would explain the large lumps of cash being put in Eadie’s bank account. £400,000 to be exact.
And she also told Billy the £10,000 “loan” from Robert looked like a pay-off. A tearful Tosh said: “If you had reported it, the police might have found out where the drugs came from. That might have stopped more from coming in. Who knows how many lives could have been saved.”
When Billy asked Tosh what she planned to do, she said she didn’t know. A broken Tosh now has a very tricky decision to make. Shop Billy to the police for failing to report a crime and no doubt get him sacked, or fail to report a crime herself. It’s a lose/lose.
Is Ed Tulloch a villain? Did he kill his own mum?
DI Ruth Calder finally fell into Ed Tulloch’s chocolate-brown eyes in this episode, something we saw coming from the moment she met him.
Sheltering from the storm, the pair decided to batten down the hatches together (not a euphenism) and stay inside sharing a bottle of rum. And that wasn’t all they shared…
As Ed and Ruth got intimately closer, DC Sandy Wilson and PC Alex Grant got closer to criminal Lewis Mitchell. They finally tracked him down and were able to arrest him for the suspected murder of Will Louden. Once they had him in custody, they found drugs, his passport, and Will’s phone on him. Incriminating evidence indeed.
However, he believed he had a bargaining chip – the name of the contact working for the Callaghans. Yes, reader, our suspicions were right all along. Ed Tulloch IS too good to be true!
As Lewis Mitchell named Ed Tulloch as the Callaghan accomplice, the camera took us back to Ruth’s house, and panned in on Ed’s very nifty running bowline knot. The very knot used to strangle Eadie Tulloch to death.
Does this mean Ed Tulloch killed his own mum? It’s a common knot, most people on Shetland would know how to tie it. And, of course, Lewis Mitchell could be lying about Ed Tulloch to get himself out of hot water. But there’s no smoke without fire, right?
All will be revealed in the final episode on Wednesday, December 10, 2025 at 9pm on BBC One.
What else happened in Shetland series 10 episode 5?
Will Louden’s fate was hanging by a thread in the penultimate episode 5 of Shetland series 10. The small-time crook was stable but still unresponsive, having been beaten into a coma by Callaghan’s heavy, Lewis Mitchell.
Meanwhile, the mystery print found at Eadie Tulloch’s house was finally matched to Tom Jameson. He’d visited Eadie to discuss Jess’ decision to put her unborn baby up for adoption. Unfortunately for Tom, he ended up caught in the crossfire of Tosh’s rage, and she tore into entirely the wrong man – leaving him utterly shattered in the process.
We also learned more about Colin Waite, the nosy neighbour who discovered Eadie’s body. His family has a long-standing feud with the Tullochs: Colin’s mum and Eadie were sworn rivals, each determined to rule the neighbourhood. Even so, Colin insisted there was no lingering hostility between him and Eadie, claiming they’d genuinely settled into being friendly neighbours.
Top 5 bombshells in Shetland series 10 episode 5
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Louden was still in a coma following the assault, a situation Ruth blamed herself for (and honestly, we can’t argue with her).
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Billy finally came clean about the drugs discovered on the Lintie.
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He also admitted to keeping evidence back from the police.
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Ed Tulloch ended up spending the night at Calder’s place while the storm raged outside.
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And that same Ed Tulloch emerged as a potential suspect.
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The final episode of Shetland series 10 airs on Wednesday, December 10, 2025 at 9pm on BBC One.
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