Episode 4 of "A Murder at the End of the World" opens with a sense of panic in the air. Following the shocking demise of Rohan, all the guests, with the exception of Andy, are ushered into a secure underground chamber, buried deep within the earth's crust, a formidable six stories beneath the surface.
Andy's absence casts a dark shadow over the already jittery group, each harboring their own suspicions and theories about the unfolding mystery. Darby recalls that moments before his fatal collapse, Rohan was frantically attempting to reach out to Heartfront, the manufacturer of his pacemaker. Lee interjects, voicing her suspicion that the device could have been hacked, given that all pacemakers manufactured after 2011 possess a wireless interface. She posits that to carry out such a feat, someone would need to tamper with the pacemaker's home monitoring system - a chilling realization that hits home when she remembers the hotel's possession of such a system.
Eva, Todd's wife, adds fuel to the fire, revealing that she had witnessed a pacemaker monitoring unit plugged in earlier that morning, a stark indication that Rohan's pacemaker had indeed been deliberately tampered with. Todd steps forward, informing the agitated crowd that they are effectively under lockdown due to the approaching superstorm, which will prevent the police from reaching them for at least two days.
Suspicions mount as whispers circulate about the possibility that inviting the guests to this remote location was a calculated move to eliminate them all. The atmosphere is tense, and the countdown to the revelation of the truth begins.
However, at this juncture, Darby's anxiety mounts as she fears she won't be able to scourge Rohan's body for crucial clues...which may vanish by the time the authorities arrive. Suddenly, a knock resonates at Darby's backdoor, and it's Sian. Darby puts Sian to the test with a choice between "vi" and "emacs," and to her relief, Sian passes with flying colors. The reason for Sian's unexpected visit soon becomes apparent.
She apologizes profusely for dismissing Darby's warnings and expresses her desire to assist in examining Rohan's body for further clues. Leveraging her knowledge of the hotel's intricate construction, acquired during its construction phase, Sian reveals a clandestine exit route. After a hurried inspection of the body, now coldly entombed in a walk-in refrigerator, Darby verifies that the pacemaker has indeed been tampered with. The hacker cunningly orchestrated a heart failure, leaving no stone unturned in their murderous plot.
Amidst their investigation, Darby discovers a red signaling device tucked away in Rohan's pocket. Upon sighting it, Sian suggests they revisit the mysterious locale Darby had trailed Rohan to the previous night. They arm themselves with Andy's extreme climate suits and head out, bracing themselves against the impending storm. Time is of the essence, and they must move swiftly.
As they traverse the treacherous terrain, their conversation turns to Lu as a potential suspect in Bill's murder. Darby posits that Lu's Artificial Insanity project, which advocated against smart homes, might hold the key to the mystery. Upon arriving at the designated location and activating the device, Sian points to a specific area where the signal seems to be emanating from. Without delay, they hop onto their snowmobiles and speed towards the source.
Darby shares a revelation with Sian, disclosing a secret plan hatched between Rohan and Bill. It seems that the mysterious signal emitted by Rohan that fateful night might have been intended for a third, unsuspecting party privy to their conspiracy. The pair's investigation takes a thrilling turn as they delve deeper into the shadowy web of deceit and intrigue surrounding Rohan's untimely demise.
As they delved deeper into the mystery, they stumbled upon a zodiac sign dangling from a rope, descending into the depths of the water. But before they could make any sense of it, Sian's anxiety rose, fearing they might get stuck in this unknown abyss. A few miles onward, the snowmobile's engine sputtered and died, leaving them stranded in the middle of nowhere.
Sian reassured Darby that their extreme climate suits would suffice to walk back to the hotel. As they trudged through the snow, they stumbled upon an unlocked car, a ray of hope in the bleak landscape. While rummaging through the car for the key, Sian's eyes fell upon an OBD terminal. She quickly harnessed her hacking skills to bring the car to life, much to Darby's surprise and suspicion.
However, they both knew that now was not the time for questions. Their focus was solely on getting back to safety. As they rode back, Sian shared with Darby how Andy had foreseen the world's demise far earlier than the predicted 2050 timeline. His apprehensions were the reason behind their suits and the secure room at the hotel, among his other technological endeavors.
Sian swore Darby to secrecy as she revealed that Andy's space project was a dead end. The PR campaign, which Sian had been involved in, was merely a smokescreen to disguise the lack of funds. Andy had been diverting the money elsewhere, but Sian was clueless as to what exactly.
The thick black ice beneath the wheels caused the car to veer dangerously, eventually tumbling and rolling several times. Darby was knocked unconscious, and her subconscious mind drifted back to a time when she and Bill were on a road trip together.
In that bygone timeline, the pair were edging closer to unraveling the killer's identity. That fateful day, they had crossed paths with another sleuth detective from the online community, Sue, at the local coroner's lab. Sue confirmed that the earrings they had discovered belonged to someone named Carmen Perez, a vital clue in their investigation.
Inside the bag of evidentiary items, they stumbled upon a ring, inscribed with the name "E. Bell." Darby speculated that she might have been his first victim, possibly someone he knew prior to his murderous spree, for serial killers often followed such patterns. Ingeniously, Bill maneuvered them into a luxurious lodge, gratis, using a clever ruse. This was the same locale from their earlier flashbacks, now fraught with a different kind of tension.
Darby indulged in a few drinks, gearing up to make a move on Bill. Although he reciprocated her kiss, he quickly retreated to the sanctuary of his bed, explaining the following morning that he had been overwhelmed with fear and the timing just wasn't right. Darby embraced him, reassuring him that it was okay to act on their mutual feelings. And so, they consummated their relationship.
Darby gradually regained consciousness in the present, as Sian hurriedly dragged her to safety back at the hotel. Through her hazy vision, Darby saw Eva tending to her wounds. But a far greater concern loomed - Sian's helmet, stubbornly refusing to come off. If it wasn't removed soon, she would perish, trapped inside the airtight helmet with dwindling oxygen. Before we could learn of Sian's fate, Darby's consciousness faded once again.
The episode culminated in a stunning revelation. After an indeterminate period, Darby awoke to find Zoomer perched on her bed, playing merrily with his stethoscope. As she drew the curtains open, allowing a flood of bright sunlight to illuminate the room, Zoomer sneezed, a telltale sign of his ACHOO Syndrome. Darby turned back in horror, as an earlier scene in the episode had revealed that Bill too suffered from the same affliction. This realization dawned on her like a thunderbolt - Zoomer was the child of Lee and Bill.
