Spoiler alert: this blog is for those watching Vigil on BBC One. Don’t read on unless you have watched episode two. Back on troubled Trident submarine HMS Vigil for the second night in a row, it was action stations as the crew desperately raced to save the boat. Meanwhile, on-board detective DCI Amy Silva (Suranne Jones) and her dry-land colleague DS Kirsten Longacre (Rose Leslie) were closing in on the killer among the crew. Cue twists, turns, masked henchmen and another murder. Let’s leave periscope depth and take the plunge. And you thought your office politics were tricky … Solid sleuthing from Longacre, who uncovered a bitter feud between Vigil’s crewmates. The two sailors who beat up CPO Craig Burke (Martin Compston) in a pub, mere weeks before his murder, turned out to be engineer Gary Walsh (Daniel Portman) and Lt Simon Hadlow (Connor Swindells). Walsh had two brothers. One, Douglas, had committed suicide after being dishonourably discharged from the navy for bullying. Burke gave evidence, hence Walsh’s hatred for his bunkmate – he blamed him for his brother’s death. Burke went to the wake to apologise, which sparked the fisticuffs. But despite taking a battering, Burke didn’t press charges. Walsh’s other brother, Sam, was a junkie, giving Gary easy access to opiates. When Silva searched Walsh’s bunk, she found a tin of sweets containing traces of heroin. Walsh, who was in the infirmary after a nitrogen blast in the reactor room, admitted to a “drunken scrap”, but denied bringing heroin aboard, let alone murder. Silva made him submit a urine sample, which he deliberately spilled on her. Charming. But the drugs test was clean. Why smuggle heroin on board if he wasn’t going to use it? To plant on Burke out of revenge. Hadlow swore that neither he nor Walsh killed Burke, mumbling about a “chain of command”. When Lt Commander Mark Prentice (Adam James) interrupted, Hadlow clammed up. Did this deadly conspiracy go almost to the top? More from Line of Duty’s ‘Balaclava Men’ Longacre had clearly been rattling cages with her awkward questions and that USB stick discovery. When she returned to Silva’s flat, where she’s pet-sitting “Cat” (short for Catherine), she interrupted a burglary being perpetrated by two hooded henchman. She put up a helluva fight – stabbing one thug with scissors and taking some wince-inducing punches for her trouble – but the thieves escaped. Licking her wounds, Longacre told boss Supt Colin Robertson (Gary Lewis) about Burke’s whistleblowing video being the tip of the iceberg, because his main files were password-protected. In a tense showdown with Rear Admiral Shaw (Stephen Dillane), Robertson tore a strip off the navy for sitting on Silva’s report of suspected murder. Shaw blamed MoD secrecy and, in a spirit of cooperation, said a boat was being prepared to replace Vigil. It would be ready in three weeks. Silva could stay on board and investigate until then. His new-found openness didn’t extend to coming clean about the missing trawler, waving it away as an accident that would end up being dumped on the agriculture and fisheries ministry. Well, it’s definitely fishy. You’re grounded! If the murderer wasn’t Walsh or Hadlow, could it be Prentice? The coxswain’s logbook proved that the smug second-in-command put Burke on a string of disciplinary charges. He had also put Walsh on report but claimed he couldn’t recall why. Silva sensed she had the killer in her sights. Prentice lost his rag and called Burke “a treacherous little shit who got what was coming to him”. What he didn’t realise was that Silva had cunningly left her phone’s voice recorder running. Insisting she was getting in the way of the crew’s work, Prentice already wanted the pesky detective confined to quarters. Now he took the law into his own hands, shoving Silva into a cabin – despite the sub’s strict “no touching” rule – and locking the door. Did pompous Prentice have something to hide? In her claustrophobic panic, Silva had flashbacks, and we learned what happened in that fateful crash. Distracted by their daughter Poppy asking her parents to marry, Silva’s partner Iain veered off the road into a loch. Struggling to escape from the car underwater, Silva was faced with a veritable Sophie’s choice. She rescued young Poppy before going back for Iain, but couldn’t get him out. Hyperventilating back in the present day, she kicked her way out via a vent. Kindly coxswain Elliot Glover (Shaun Evans) comforted her as she told him about the tragedy – holding her hand despite that no-touching rule. Signs of sub-aqua romance? Prentice? You’re fired After breaking out of her impromptu prison, Silva arrested Prentice on suspicion of Burke’s murder. In a Line of Duty-esque interview scene lasting nine minutes – all that was missing was AC-12’s trademark long beep – she drilled down to the truth. Prentice saw through Walsh’s clumsy attempt to frame Burke for possession and put him on a warning. He had accused Burke of treachery because he somehow knew he was dating a peace protester. After he dismissed Burke from duties, the pair clashed on the missile deck. Burke hit his head, witnessed by Hadlow. Prentice went back later to apologise and found Burke dead in his bunk. He panicked and planted the confiscated drugs to make it look like an overdose. Meanwhile, Glover found Burke’s missing fleece. Prentice had stripped it from his body and hidden it because of incriminating bloodstains. He was bang to rights and Commander Neil Newsome (Paterson Joseph) stood his deputy down. Now it was Prentice who was confined to quarters. Result. Tried turning it off and on again? In the midst of all this crime-solving, there was the small matter of the submarine’s emergency shutdown. No one could diagnose the cause. Back-up power would only last three hours. Talk about a high-stakes deadline. Just when things couldn’t get much more hairy, the sub was suddenly on a collision course with a tanker. They managed to narrowly dive under it, but was something interfering with HMS Vigil’s systems? An enemy sub, maybe? In the nick of time, Hadlow and Adams restarted the reactor and regained full power, allowing Vigil to return to a safe depth. Cue a relieved round of applause from the crew. Don’t get too relaxed, shipmates. There are still four episodes of deep-sea danger to go. The case just got thrown wide open Just as Silva thought she had cracked the case, surprise new evidence emerged in a late twist. Finding a strange stain on Burke’s fleece, she realised he’d actually been poisoned. Engineer Adams (Tom Gill), who had given him CPR, was suffering from blurred vision and fluey symptoms. Prentice assumed he had accidentally killed him, but Burke hadn’t died of a head wound after all. Now Silva was in pursuit of a deadly poisoner. Enjoy your next meal in the mess, shipmates. Jade paid the ultimate price Events took a tragic turn on land. Protester Jade Antoniak (Lauren Lyle) had formed a wary bond with Longacre. After the burglary, she warned that MI5 watched activist groups and that shadowy forces were in play. Cop or not, Longacre wasn’t safe. In return, Longacre made Jade promise to call if anything worried her. Determined to expose her boyfriend’s murder, Jade agreed to meet an anonymous source who knew what happened to Craig. She got spooked at their roadside rendezvous and phoned Longacre, but too late. Longacre found her floating in a loch and desperately administered CPR, to no avail. Burke and his girlfriend had now both been murdered. Jade’s final act was to text Longacre the word “purity” – the password for Burke’s files. Submarine-speak decoded “EO” means engineering officer. “The EPM” is the submarine’s emergency propulsion motor, while “scram” refers to the sudden shutdown of a nuclear reactor. Notes and observations When Burke’s body was carried through the boat, did you spot how galley chef Jackie Hamilton (Anita Vetesse) was the only crew member in tears? If there was poison in his food, who better to administer it? That haunting theme song is Fuel to Fire by Danish neoclassical diva Agnes Obel – a regular on moody drama soundtracks. We’re getting regular glimpses of peace camp leader Ben Oakley (Cal MacAninch) glowering in the background. Something tells me he’ll have a bigger part to play. Could he even be a spy on behalf of the security services? After this bank holiday double whammy, Vigil now reverts to its regular Sunday slot. Rejoin me at 10pm on 5 September for a deep dive into episode three. In the meantime, me hearties, leave your thoughts and theories in the coxswain’s log below …