BBC One’s Vigil is weaving a truly twisted tapestry, isn’t it? 

Tonight’s episode (the third, for anyone counting) saw DCI Amy Silva (Suranne Jones) continue to do her best to figure out who murdered Craig Burke (Martin Compston) – and, more importantly, why. However, thanks to new information from her erstwhile lover on solid ground, DS Kirsten Longacre (Rose Leslie), Amy finds herself stumbling headfirst into a mystery unlike any other.

First up, there’s the fact that Lt Tiffany Docherty (Anjli Mohindra) – aka the sub’s doctor – falsified drug tests to cover up a situation in Florida. A situation, this writer hastens to add, which led to the deaths of two contractors, not to mention the very sudden transferral of one of the sub’s crew.

Secondly, there’s Burke’s incriminating photo of Docherty, featuring a mysterious man with a dragon tattoo. As it turns out, that mysterious man is none other than Amy’s one-time ally, Glover (Shaun Evans). Which, considering the coxswain has a wife and child on the surface, is… well, is it a motive for murder?

Thirdly, there’s the fact that Burke’s protestor girlfriend, Jade (Lauren Lyle), has now been killed off, too. And, after a chat with Burke’s embittered rival, Gary Walsh (Daniel Portman), Amy deduces that both Burke and Jade had evidence proving that the Navy’s Vanguard-class submarines aren’t “fit for purpose”. 

“These boats are on their last legs and nobody wants to talk about it. There’s too much at stake,” says Walsh. “Burke talked a lot of shite, but he was right about that.

Could it be, then, that these murders are just a small part of a much bigger, and far more classic, “bury the evidence” conspiracy?

As ever, Vigil has left us with a lot of questions. Let’s do our best to unravel them all, shall we?

Why did the USA launch an undersea attack in British waters?

It’s a staggering act of hostility from a supposed ally, but it seems as if a Los Angeles submarine was responsible for a) stalking the HMS Vigil and b) dragging Mhairi Finnea – aka the missing trawler from episode one – down to the bottom of the ocean.

Why, though? Working separately, Amy and Kirsten have both uncovered evidence to suggest that the crew of the HMS Vigil caused a lot of trouble during their shore leave in Florida. They went out, they got drunk (and high on recreational drugs), and they messed up bigtime when they returned to the sub, resulting in an unprecedented pressure build-up and near hydrogen explosion.

Yes, they managed to avoid a Hiroshima-style catastrophe, but the accident saw two contractors cooked alive. And, while the bodies were dumped in a deep water harbour and the whole situation promptly hushed up, it’s not exactly… it’s not exactly the way you’d expect the Navy to behave on foreign shores.

Is it the sort of incident, though, that would lead to the USA staging a covert attack on the Royal Navy? Really? Or is there simply someone out there who wants us to think that it is?

Who killed Jade?

At first, it seemed as if Mark Hill (Oliver Lansley) was the one who bumped off poor Jade. Then, we figured it had to be Mark’s shady politician boss, Patrick Cruden (Stephen McCole). But then Kirsten sat him down in an office, and the truth poured out.

“It’s not what you think,” he told her, revealing that the late Jade was actually his illegitimate daughter. “I had a fling with her mother… my wife didn’t know about her, still doesn’t.”

So, yes, that’s why Patrick and Mark set up a company to pop £1,000 into Jade’s account on a monthly basis. And, if Patrick’s tears are to be believed, he’s actually pretty devastated at the loss of his child. 

When Kirsten probed him for more information about Jade, Patrick was incredibly forthcoming.

“She was being followed,” he said. “She had her laptop stolen, and was convinced MI5 had people in the Dunloch Peace Camp.”

He also adds that Burke had evidence that (you’re going to hear this a lot) the Navy’s submarines aren’t “fit for purpose,” seemingly implying a top-level conspiracy involving the UK’s biggest forces. Which brings us nicely to our next question…

What do the MI5 want with Kirsten?

If there’s one thing we’ve learned from Line Of Duty, it’s this; being followed by a black SUV always ends in disaster. And so, when Kirsten spotted one on her tail, we feared the worst – especially when she decided to lure it to the top of a deserted multi-storey carpark, leap out without backup in sight, and confront the drivers head-on.

As it turned out, though, the people driving the SUV weren’t heavily-armed men in balaclavas. Instead, it was the two MI5 agents we met from earlier in the episode – and they had very stern expressions on their faces indeed.

Now, maybe they’re looking to forge an alliance with the police, so that they can investigate the Navy’s flaws together. Maybe they’re hoping to warn Kirsten off the case. Or maybe, just maybe, they’re the dodgy ones in all of this and they’re hoping to stop anything else being leaked to the press.

Sadly, we have to wait until next week to find out more. What we know for sure, however, is that these two agents have just been made aware of the Los Angeles submarine lurking in Scottish waters, so that’s bound to make for another twist or two.

Did Lt Tiffany Docherty kill Craig Burke?

As the sub’s doctor and surgeon, Docherty has the knowledge that could allow her to easily kill someone and cover it up. She also gave Burke tablets an hour before he died, claiming they were paracetamol, and said she did not spot the injury at the back of his head that seemed to cause his death. And, as we learned in episode three, she also falsified the crew’s drug tests in Florida – which mad many assume that Burke was lying when he said he’d been spiked with LSD (a claim he later proved with his own private drug test).

Now, Docherty  has denied she was pressured into partaking in the coverup, insisting that she’d only done so because the Vigil crewmembers involved were her friends. 

“These people put up with loneliness and boredom and a complete lack of privacy,” she told Amy, insisting that they deserved to “let off steam” without losing their careers over it.

Amy, though, makes it all too clear that she thinks Docherty is lying: the police detective is convinced that the sub’s doctor was strongarmed into falsifying those records… but by who?

Well, we have a theory…

What happened between Docherty and Glover?

We know that Glover and Docherty had an illicit affair – one which Burke knew about, too, after stealing incriminating photos from Glover’s phone. But, as this episode makes all too clear, there is tension between the one-time couple; when he swooped in to kiss her, she turned her cheek and asked him to leave. And she also seemed deeply uncomfortable in the married man’s presence.

Could it be, then, that Glover pressured Docherty into staging the coverup? He isn’t just her lover, after all; he also holds a more senior position as the sub’s coxswain, which means he is well within his rights to give orders.

On that same note, could it be that Glover asked Docherty for her help in covering up Burke’s murder, too? She did seem confused when she learned that Burke had evidence of their affair, which would suggest she didn’t know about the stolen photos. Glover, however, knew – and hid this from her. Why?

Maybe, as some viewers have suggested on Twitter, he was simply trying to hide the fact that he had a motive for killing Burke himself. Food for thought, anyway.

How is the chef involved in all of this?

At the risk of getting all Cluedo on you all, it’s worth remembering that Jackie Hamilton (Anita Vettesse) is the only ­member of crew on board who seemed to show any emotion following Burke’s death. She cried when his body was carried through the galley, and the chef was the only one crying during his memorial, too.

Now, we know that Glover told Amy this might be down to the fact that Jackie’s own son has problems with drugs. But could her crying be guilt rather than sadness? As the sub’s chef, after all, she was in the best position to slip a certain poisonous something into Burke’s food – although everyone aboard has stated that he didn’t visit the mess hall in the hours before his death.

Hmm.

And, finally, should we be watching Newsome more closely?

Newsome was fully aware of the incident in Florida, and involved in its coverup. And, when a drunken Walsh brings up the subject of Burke with him, the captain asks if Walsh is threatening him.

Up until now, we thought Newsome was on the level. A little intense (and super straight-laced), perhaps, but a reasonably calm man with a good head on his shoulders. But all of the above gives us cause to doubt him, as does his cold little tribute to Burke at the memorial.

“We are as we were – a professional crew committed to the mission, to each other, and keeping Britain safe,” he told the crew at the time. “That task remains paramount.”

Anyone else thinking this is the sort of person who might be willing to do absolutely anything to ensure his mission of travelling through UK waters undetected goes without a hitch?

The next episode of Vigil will air Sunday 12 September, 9pm on BBC One. 

Read our recap of Vigil episode two. 

Images: BBC