The episode kicks off with Tess Avery (portrayed by Dolly Lewis) gliding through the water of a pool with effortless grace. Upon returning to the sanctuary of her apartment, she inadvertently sends a glass cascading to the floor in a clatter of shards. Briefly pausing, she rises and drifts towards the balcony, where an eerie sensation of fiery embers envelops her, almost tangible in the air.
Flashing back, a younger Tess Avery (played by Jenna Lamb) is wrapped in an embrace with someone amidst the chaos of a police scene. Snapping back to the present, Tess retreats indoors, firmly shutting the door behind her.
The following morning, Sunny Patel/Sunita Sharma (Agam Darshi) holds a sea glass, a silver spoon, and a wine cork in her hands, a feeling of "impending doom" settling over her like a shroud. She ponders whether these items might be part of a cryptic message. At the site of a motor vehicle accident, Detective Leo Li (Tony Giroux) informs Tess that the vehicle is registered to 45-year-old Sheila Summers (Donna Milburn). He reveals the discovery of a Shetland Chemicals security pass within the car, suggesting Summers had embarked on her journey home from work. As they assess the scene through live footage, Sunny notes that the head wound mirrors the spider webbing pattern etched onto the windshield. Li pronounces Summers dead on impact, yet Tess remains unconvinced, the body's location some 20 feet from the vehicle raising suspicions. She detects potential knee prints nearby, prompting Sunny to wonder if someone had straddled Summers. Tess posits that someone, possibly a passenger, attempted CPR. The first officer at the scene had claimed Summers was already deceased, her body oddly posed with arms crossed, almost like a funeral tableau. Tess detects a faint, sweet aroma reminiscent of dry-cleaning fluid.
Lucas Avery (Alec Santos) arrives to collect Tess from the scene, presenting her with a gift and revealing his intention to marry Craig. She insists it's premature, her objections falling on deaf ears. Lucas argues passionately that she cannot deny his love, while she reminds him of their parents' toxic legacy—a couple built to inflict pain. He refuses to listen further, his mind made up.
Moments later, Lucas waits impatiently in his car as Li and Tess head inside to confront Jordan Brocker (Antonio Cayonne), the manager of the Shetland Chemicals plant. A security guard (Thomas Strumpski)confiscates Li's gun as protocol demands. Outside, Walter Farrow (Ryan Robbins) arrives, methodically loading a magazine into his rifle, the tension in the air palpable.Superintendent Bennett (Roger Cross) convenes a compulsory meeting with Agent Mitchell (Ben Cotton) to present his perspective on a four-year-old homicide case. Bennett recounts how Biochemist Rigby Daniels met his untimely demise, stabbed in the sanctity of his own bed. The incriminating evidence fingered Daniels' mistress, Sunita Sharma, as the perpetrator. He alleges that Lieutenant Taylor exerted undue pressure on him to charge Sharma, yet he harbored doubts about her guilt. Taylor sweetened the deal with a promotion in exchange for Bennett's relinquishment of the case, which he reluctantly accepted. Bennett received a mysterious call from an undisclosed number, the voice on the other end claiming affiliation with influential figures who demanded the cessation of the Daniels' case investigation, diligently pursued by Bennett's team. When Bennett failed to comply, the caller issued ominous threats against him and his family.
Meanwhile, at Shetland Chemicals, an armed Walter Farrow storms the premises. Li and Tess swiftly inform Brocker of Summers' tragic demise. Brocker reveals that Summers was a seasoned maintenance technician of the old guard. Tess detects a faint, cloying aroma reminiscent of the accident scene, which Brocker identifies as bromopropane, a highly flammable solvent. Gunshots echo through the facility, prompting Sunny to urge Tess to evacuate. Li, Tess, and Brocker scramble for cover behind massive vats. Li engages Farrow in a physical altercation. Brocker guides Tess to safety within a confined room. Sunny radios for reinforcement as Li sustains an injury. Farrow retrieves his firearm, and Tess is warned of his impending arrival. Brocker ushers Tess away from the door just as Farrow enters the room, scanning the surroundings before abruptly departing. Li phones Tess, intending to retrieve his gun. The Emergency Containment System is activated, sealing off the production area, condemning anyone inside to confinement. Farrow confides in Debra (Yvette Lu), asserting his actions are retribution for Summers' fate, vowing to make "him" see the injustice done to Summers. He silences the other workers with tape.
Trapped within the production area, Leo confesses to Tess that he has been shot. Brocker identifies the shooter as Walter Farrow, a maintenance worker. Farrow's incoming call flashes on Brocker's phone, and Li answers, revealing his identity. Farrow warns that his sole target is Brocker, whom he holds accountable for Summers' death. Tess queries Brocker about the allegations leveled against him, to which he repeatedly responds by vowing to track down Farrow. She reassures him of their commitment to ensuring his safety.As Lucas slumbers peacefully in his vehicle outside Shetland Chemicals, backup arrives on the scene. As the reinforcement approaches the officers, they swiftly unholster their weapons and command him to lie prone on the ground. Intervening swiftly, Jake Campbell (played by Daniel Gillies) steps forward.
Inside the production area, Li pulls aside his shirt to reveal a gunshot wound to his chest, assurances of itstriviality ringing hollow. Sunny, skeptical, insists that Tess takes immediate action to seal the wound, wary of the impending collapse of his lung. Tess, alert and concerned, contacts Jake to update him on Li’s critical condition. Jake informs her that eight additional workers are trapped alongside them. Tess identifies Walter Farrow as the shooter, to which Jake responds by instructing her to stay clear of danger's path. Tess, however, is steadfast in her refusal to allow Lucas's apprehension.
Taking charge, Sergeant Dietrich (portrayed by Lexa Doig) assumes command of the operation. Tess hastily applies a makeshift dressing to Li’s wound, sharing with him the unforeseen news of Lucas’s impending marriage to Craig. She emphasizes that love, like their marriage, is not eternal. Sunny draws Tess’s attention to several photographs depicting Farrow and Summers together, fueling Tess’s belief that Farrow was not only Summers’ passenger during the fateful crash but also her romantic partner. Li’s optimism begins to wane, fearing he may not survive this ordeal.
Using a loudspeaker, Farrow issues a demands for Brocker to be surrendered to him. As Li’s strength gives way and he collapses, Tess urges Brocker to stay with him. Farrow boasts of his ability to incapacitate Brocker without firing a shot, just as the production area begins to fill with smoke.
Elsewhere, Mitchell inquires about Bennett’s handling of the mysterious threats. Bennett claims to have stalled until the calls ceased, then embarked on a quest for answers. He reveals that he discovered Mitchell had launched an investigation into the cover-up and subsequently sought out Tess to rectify matters. Mitchell excuses himself to make some calls.
Outside Shetland Chemicals, Dietrich gives Jake strict orders not to inform Tess and Li of their impending entry. Lucas, filled with regret over his argument with Tess, finds reassurance from Jake that all will be well. Inside, Tess detects the pungent odor of bromopropane just as the lights flicker and go out. Sunny warns of the Emergency Response Team’s impending breach. Tess tries calling Jake on his phone, to no avail.
As Dietrich and her team prepare to storm the building, Tess, via the loudspeaker, alerts them to the bromopropane threat. Jake, with urgency, pleads with Dietrich to halt the breach. Reluctantly, she orders her team to stand down but laments the time-consuming process of manually dismantling the door.Mia Moss, alias Alice Christina-Corrigan, bestows Matt with three delightful donuts, pledging the remainder as a reward once she secures the role of accessibility liaison. As he ponders their future, a call from Tess interrupts his thoughts, pleading for his assistance. While Matt delves into the technical blueprints of Shetland Chemicals, Tess recounts their dire predicament. He discovers an emergency ventilation system, powered by an uninterruptible supply, ready to serve its purpose.
Despite Sunny's misgivings, Tess, driven by Matt's guidance, sets forth, pausing only to call Lucas, offering a heartfelt apology. As she unwraps his gift, a delicate swallow ornament comes to light, reminding her of a childhood illusion about swallows shared by their mother. Lucas seizes the moment, asking Tess to stand as his maid of honor. Her response is swift and abrupt as she terminates the call. Matt leads Tess toward the tanking room, amidst growing tension.
Through the loudspeaker, Farrow's menacing voice echoes, threatening Brocker. Suddenly, Tess's communication device is disrupted, severing their link. A eerie hiss fills the air, matching Matt's earlier warning. Tess catches a fleeting glimpse of Farrow, his figure blurred, casting blame on Brocker for Summers' untimely demise. Brocker lunges from behind, gripping Tess tightly.
Matt and Sunny deliberate their next steps, amidst uncertainty. A call from Jake interjects, his curiosity piqued about Tess's whereabouts. Matt explains their attempt to activate the emergency ventilation, only to be cut off by the failing signal. With determination, Matt guides Jake into the facility. Meanwhile, Brocker drags Tess closer to the ventilation system, her senses overwhelmed by the perception of fiery sparks surrounding her.
Farrow advances, his gun trained on them, a grim smile playing on his lips. Tess warns him of the lethal bromopropane gases permeating the air; a single shot could spell doom for all. Farrow ignores her, insisting he's already a walking dead, poisoned like Summers. He demands Brocker's confession under threat of death, accusing him of falsifying a work order to cover a corroded valve that led to their exposure. Brocker, contrite, offers a mea culpa.
In a swift motion, Tess plunges the swallow ornament into Farrow's leg, leaping atop him. Jake, peering through a vent, bears witness to the unfolding drama. Tess wrests Farrow's gun from him, turning it against its original wielder. The scene is set for a climactic confrontation, with each character's fate hanging in the balance.Mitchell extends a heartfelt apology to Bennett for his prolonged absence, his tone laden with sincerity. Bennett, in turn, relinquishes his badge with a sigh, surrendering to the weight of the moment. Mitchell then unravels a bombshell, revealing that Frank Smith was the mastermind behind the menacing phone calls, which mysteriously ceased after Smith's ill-fated intrusion into Sunny's abode ended in his untimely demise. Sunny, it transpires, was the head of security at a pharmaceutical giant helmed by Graham Langston. Bennett's accusation follows swiftly, implicating both Smith and Langston in the grim scheme that led to Daniels' murder.
Mitchell speculates that their motive revolved around Daniels' research on a drug that had been yanked off the market, sparking intrigue and danger. Bennett, however, feigns ignorance, denying any awareness of the missing research. Meanwhile, two officers usher Farrow towards a waiting police cruiser, the air thick with tension.
Sunny reassures Tess with unwavering conviction, her trust in Tess unshaken. Leo, recovering from his ordeal, vows to persevere, while Tess insists that he must live to narrate tales of her bravery. His memory of unconsciousness fades as Jake expresses boundless pride in his daughter. Farrow's accusations against Brocker promise to be scrutinized thoroughly, the wheels of justice beginning to turn.
Elsewhere, Lucas sweeps Tess off her feet in a playful twirl, vowing never again to chauffeur her. She humorously pleads with him not to let her wear a formal dress at the wedding, and he playfully refuses the request, leaving the door slightly ajar for future negotiations. In a different corner, Matt extends an invitation to Mia for dinner, which she accepts with a smile, the promise of new beginnings brewing.
At her home, Tess pours herself a drink, the flames of her inner turmoil flickering anew. Her mind drifts back to her mother's gentle words about the return of the swallows. As she gazes at a photo of her and Daniels, her eyes catch a glimpse of a "Robinson Crusoe" novel perched on a shelf behind him. Intrigued, she retrieves the book, carefully tears open its binding, and to her astonishment, a USB stick drops to the floor. With a mix of awe and determination, she declares it to be Daniels' missing research, the piece of the puzzle that could unlock countless secrets.
