The episode kicks off with an intense scene as Patience Evans (portrayed by Ella Maisy Purvis), visibly anxious, undergoes rigorous interrogation. A female detective, her voice tinged with curiosity, inquiries about the reason behind her visit to the car park. Patience, however, remains tight-lipped, offering no response. Through the observing two-way mirror, DCI Calvin Baxter (Mark Benton) can't contain his irritation. DI Bea Metcalf (Laura) Fraser) steps in to inform him of Patience's involvement in an autism support group. Just then, Retired DCI Douglas Gilmour (Adrian Rawlings) bursts in, lambasting Baxter for detaining an innocent woman. Baxter retaliates by stating that Patience came voluntarily. Metcalf, puzzled, wonders aloud about Gilmour's heightened concern for Patience's wellbeing. Patience in the case before revealing himself as her godfather. Baxter, somewhat relenting, notifies Gilmour that Patience is free to depart, although the investigation is beginning to resemble a murder inquiry.
Metcalf then enters the interrogation room, her tone apologetic as she pleads with Patience to place her trust in her. Patience's mind drifts back to a haunting memory—Dr. Brendan Clark (Joseph Arkley) inquiring of George Evans (Jamie Maclachlan) whether his wife shared the same mental condition as young Patience (played by Ava Cook). Snapping back to the present, Patience confides in Metcalf, revealing her visit to the car park was in search of a cigar. Metcalf probes further, asking if it was akin to the cigar discovered at Neal Jamieson's murder scene. Patience affirms, noting a similar cigar resided in Clark's treatment room, and had she found one in the car park, it would have bridged the two cases.
Metcalf delves into crime scene photographs, realizing the cigar in question is a Cockscomb. She informs DS Jake Hunter (Nathan Welsh) that Patience should never have been subjected to questioning. Hunter, tongue-in-cheek, remarks that she shouldn't have meddled and wonders why she never disclosed her autism. Subsequently, Metcalf and Hunter scrutinize Chopra's vehicle, uncovering a Cockscomb cigar concealed within the exhaust pipe.
At the City of York Police Department, Metcalf and Baxter scrutinize CCTV footage, depicting a figure in a hoodie planting the cigar in Chopra's exhaust. The footage originates from an office building with a clear view of the car park. She reveals that DC Will Akbari (Ali Ariaie) has discovered similar footage of the same individual within a parking garage. Seizing the opportunity, she proposes Patience as a civilian assistant on her investigation team. Baxter, though reluctant, concurs but insists she first discuss it with Gilmour.
Shortly thereafter, Gilmour presents Metcalf with a photo album. He narrates how George refused to institutionalize Patience. Metcalf commends him for his decision. Through a flashback, we witness George catching young Patience perusing a police file. He hastily gathers the documents, her inquisitive mind asking about a toxicology report. He glances at Gilmour but remains silent. Returning to the present, Gilmour recounts how Patience gradually began to open up after that incident. Metcalf finds the anecdote "bizarre," learning that George brought home police files for her perusal. He passed away in a duty-related car accident, and her mother deserted her when she was just six years old.
Metcalf imparted to Patience that Baxter had given his blessing for her to join his investigative team. However, Patience, apprehensive about the unpredictable nature of the work potentially overwhelming her, steadfastly declined and insisted on continuing with her routine of taking the bus. Metcalf then confided in Billy Thompson (Connor Curren), revealing her attempts to persuade Patience to come on board. Billy shed light on how individuals on the autism spectrum often possess a unique interest that serves as a soothing sanctuary, in Patience's case, puzzles.
Moments later, Metcalf expressed her gratitude to Patience for breathing life into the investigation. She pondered aloud about the significance of the cigars, likening the investigation to a puzzle with crucial pieces missing, before driving off. Subsequently, Patience delved into the case files of Jamieson and Clark.
At the police station, Metcalf posited that whoever administered scopolamine to the victims knew that an excessive dose could be fatal, while too little would prove ineffective. He revealed that Café Caracol, a local vendor owned by immigrants from Belize, was the sole seller of Cockscomb cigars. A text from Patience simply reading "Belize" popped up on Metcalf's phone.
At the Criminal Records Office, Patience unveiled her investigative board to Metcalf. She highlighted that Brugmansia Candida, also known as "Angel's Trumpet," a natural source of scopolamine, was cultivated in Belize. She pointed to a crime scene photograph featuring a Belize travel guide that evoked no childhood memories in Patience. Another photo showed Jamieson at Houston Airport, just before his departure to Belize on October 8, 2016. Patience also uncovered evidence of Chopra serving as an expert witness for the CPS years ago, having undergone inoculations in accordance with Foreign Office travel advice for Belize.
Patience and Metcalf then met with James Cooper (Christian Contreras), Director of Marketing at Curabellum. Cooper claimed to have attended a 2016 conference but couldn't recall Jamieson being present. Metcalf informed him that two conference attendees had passed away around the same time as Jamieson, prompting Cooper to inquire if suicide was a possibility. Patience suggested the possibility of third-party involvement. Metcalf requested a list of delegates, to which Cooper responded that their legal representatives would handle the matter. Patience inquired if Cooper was his birth name, to which he replied that he had changed it due to frequent mispronunciations.
Later, Patience vented to Billy about her desire to solve the case but was frustrated by the constraints. He offered to discuss it with her. Meanwhile, at the police department, Baxter briefed on local street crimes. Metcalf, engrossed in a puzzle, abruptly left. Shortly after, she revealed to Hunter that James Cooper was actually Jaime Cobre, previously charged with soliciting sexual services in public—an act legal in Belize. She speculated that Clark, Chopra, Jamieson, and Cooper might have been entangled in some illicit activity in San Pedro, Belize. Patience and Billy soon joined Metcalf to continue their discussion.
Cooper is in the midst of his preparations for departure when he informs someone over the phone of his ailment, announcing his absence from the office until the ensuing week. Just then, a figure draped in a hoodie enters the scene. Over at the police station, Metcalf registers his displeasure with Patience for discussing the case with Billy. Billy reveals that his hacker girlfriend infiltrated Curabellum’s database to procure an attendance list from the 2016 conference and Cooper’s emails. A particular email unearths Cooper’s arrangement of a boat charter in San Pedro, aboard which were Jamieson, Clarke, Chopra, and Cooper himself. Billy cautions that Cooper is aware of their pursuit, equipped with hacking alert software on his computer.
Metcalf and Hunter arrive at Cooper’s residence to find him perched precariously on the rooftop. Hunter endeavors to dissuade him from jumping, yet Cooper takes the plunge, crashing onto a car below. Later, Patience and Metcalf scrutinize the crime scene, with Patience instructing Crime Scene Manager Elliot Scott (Tom Lewis) to collect swabs for traces of scopolamine. She notes that only the right side of the furniture has been dusted for fingerprints. Metcalf introduces Patience, who specializes in criminal records, to Scott.
At the police station, Metcalf informs Baxter that Cooper’s condition is critical. Meanwhile, fingerprints belonging to Yemaya Vasquez (Joana Borja) are discovered at the crime scene. Patience reminisces about Yemaya, a cleaner at the Railway Hotel, who was fingerprinted after Jamieson’s demise.
At the Railway Hotel, Hunter and Metcalf learn of Yemaya’s resignation. They attempt to reach her emergency contact, Maria (Jimena Larraguivel), but only manage to leave a voicemail in Spanish, instructing them to call her work number in case of urgency. Patience, recalling the number from memory, impresses Hunter and Metcalf. Metcalf recognizes it as the Café Caracol’s number.
Shortly afterward, Maria informs them that Yemaya left for Belize the previous night. Metcalf and Hunter search the premises and discover Yemaya hiding upstairs. She attempts to escape but is apprehended by Hunter. During a video chat, an embassy official (Ady Van De Plas) informs Metcalf that Yemaya had reported her sister, Violetta, missing after she failed to return from a boat trip in October 2016. The photograph of Violetta bears a striking resemblance to Yemaya.
Later, Metcalf and Hunter delve into Yemaya’s apartment, uncovering an altar dedicated to Chango. Maria explains that Chango can be invoked to seek revenge upon enemies, with Cockscomb cigars offered to maintain his favor. She further reveals that Friday is Chango’s special day and four is his sacred number, adding depth and intrigue to the unfolding mystery.
Yemaya, with a confession heavy on her lips, admitted to terminating the lives of Cooper, Jamieson, Clark, and Chopra. She asserted that the bloodstains traced back to none other than Violetta. Initially, Cooper had enticed her with a $500 offer to serve refreshments aboard a seafaring excursion. Upon arriving to board the vessel, Yemaya noticed Violetta's absence, her presence sorely missed. Amidst her confusion, she stumbled upon a matchbook, its significance yet to unfold. Facing the camera lens, Yemaya's eyes reflected devotion as she vocalized her prayers to Chango.
Elsewhere, in a cozy café filled with the aroma of freshly brewed coffee, Patience steadfastly insisted on reclaiming her familiar table. Metcalf, joining her, demonstrated remarkable ingenuity by solving a perplexing nine-dot puzzle—a feat achieved by thinking beyond conventional boundaries.
