The second installment of "Towards Zero" unfurls with Inspector Leach miraculously washing ashore, his survival of the plummet a stark contrast to the dread surrounding Sylvia. Amidst this, the ensemble decides to venture to the beach, defying Lady Tressilian's invitation to linger for lunch in her opulent abode.
During their sojourn by the sea, Thomas confesses to Mary a long-forgotten love for Audrey from their youthful days, emphasizing the passage of time that has dimmed those sentiments. Meanwhile, an unspoken rivalry brews between Audrey and Kay over Neville, whose affections consistently lean towards Audrey, much to Kay's chagrin.
Elsewhere, Leach awakens in a hospital bed, his fate hanging by a thread yet miraculously intact.
Bankruptcy-stricken, Thomas pleads for Lady Tressilian's financial assistance, resorting to threats of exposing Neville for a brother's alleged murder—a claim met with skepticism except in Thomas's deluded mind.
As twilight descends, the group adjourns to a pleasure hotel for a night of revelry. Kay attempts to stake her claim on Neville amidst Audrey's presence, but her efforts falter as Neville and Audrey find themselves lost in an intimate dance, leaving Kay partnered with another. Concurrently, Lady Tressilian, with Mr. Treves by her side, amends her will, her demeanor hinting at long-depressed anger lurking beneath the surface.
Upon their return, Lady Tressilian, irked by their nocturnal escapades, refuses to grant them audience. In contrast, Mary invites Louis Morel, a shadowy fixer at the hotel whose past remains concealed from the others. Mr. Treves' cryptic remark that unraveling a murder mystery necessitates delving "towards zero" looms heavy in the air.
However, tensions escalate when Neville discovers Morel's past connection with Kay. In parallel, Audrey misplaces her compact, prompting her to venture out in search of it, Neville trailing her in a mix of frustration and concern. The night, once promising camaraderie, now teems with secrets, suspicions, and simmering passions.
Rather than locating the compact, Neville and Audrey embarked on a scandalous liaison right on the stairs, their tryst unwittingly observed by Kay. Enraged beyond measure, Kay vowed never to grant Neville a divorce, declaring her preference for terminating their lives instead. Lady Tressilian, catching wind of this scandal, compelled Neville to reconcile with Kay.
Later that day, Neville entrusted the housekeeper with the task of checking on Lady Tressilian just as she wrapped up brewing her tea. Meanwhile, Macdonald, with a sly grin, slipped a bottle of Valium from the kitchen before making his way to the pleasure hotel for the evening.
The following morning, Mary stumbled upon the lifeless body of the housekeeper, and shortly thereafter, Lady Tressilian was discovered in a pool of her own blood, having suffered a fatal blow to the head delivered by a blunt object. The police swiftly swung into action, gathering all involved parties for questioning.
During the grueling interrogations, Inspector Leach unearthed Thomas's dark history of blackmail and Lady Tressilian's recently revised will. Neville maintained his alibi, claiming to have been out drinking the previous night, while Thomas steadfastly accused Neville of deliberately slaying his own brother. Meanwhile, Leach unearthed crucial evidence: letters exchanged between Mary and Thomas revealed her betrayal of Lady Tressilian, despite her previous dedication to caring for her ailing father full-time before being welcomed into Lady Tressilian's home.
As Leach delved deeper into Lady Tressilian's quarters, he found a shattered photograph of her husband, pondering over the reason behind her anger towards him. The murder weapon, Neville's golf club, was discovered near the shoreline, casting a dark shadow over Neville's innocence. Despite this incriminating evidence, the brief four-minute window during which Neville was unaccounted for fell short of providing him with sufficient time to drive back to the house and commit the murder.
Meanwhile, the police discover Macdonald in possession of the bottle of Valium, the tranquilizer that had stirred up quite a commotion. Gradually, the truth unravels: Macdonald is revealed to be the illegitimate offspring of Lady Tressilian's husband, shedding light on her intense animosity towards him—she had callously allowed him to perish when his boat sank. Mr. Treves emphasizes the paramountcy of a compelling motive, ultimately paving the way for Macdonald's arrest.
Yet, later that fateful night, another soul meets an untimely demise, suffocated in the darkness. Meanwhile, Neville passes the night in the company of Audrey, oblivious to the grim events unfolding elsewhere. The episode concludes on this eerie, foreboding note, leaving viewers on the edge of their seats.
