The thrilling sequel to this labyrinthine mystery kicks off with Ember contemplating the picture of Mack and Amy she stumbled upon, taken on the eve of Amy's disappearance. Hannah appears indifferent, but Ember bears the burden of suspicion like a mountain on her shoulders. Determined, Ember approaches Riz, who's still delving into Amy Knightly's vanishing act with her podcast. Ember desires to join the investigative quest, but Riz proposes an interview instead. Ember declines, yet divulges a rumor about Amy's parents struggling financially and taking out a life insurance policy in her name. This piques Riz's curiosity, and their conversation deepens as Riz reveals an eyewitness saw Amy walking towards the lake the night she vanished. Strangely, the lake wasn't searched in Amy's hunt.
Ember struggles to gain access to Amy's police file, lacking the necessary authority from her boss. Frustrated, she accompanies Hitch to the hospital, where they encounter the Ashbys by Miranda's newborn's incubator. Hitch mischievously suggests Liam could be the father, adding fuel to the fire.
At Sylvia's, Ember sneaks in to retrieve her old photo albums, revealing Sylvia as her mother. They reminisce over snapshots from Ember's 17th birthday, a relief for Ember as her mother reveals it was the same night Amy disappeared and Mack stayed at their home. This assurance eases Ember's suspicions, knowing Mack couldn't have been involved if he was with them. Sylvia mentions she's been communicating with Amy and intends to expose her father's lies, but Ember dismisses her mother's clairvoyance and returns home.
The next morning, Ember and Hannah discuss commemorating Mack's first death anniversary by scattering his ashes. Ember then chauffeurs Hannah to school in Mack's vintage car, Hannah noticeably more at ease knowing Mack couldn't be linked to Amy's disappearance.
The episode rewinds 17 years, depicting Caitlin being dropped off at school by her mother, who warns her about Amy's negative influence. Caitlin dismisses the advice. Returning to the present, Ember invites Arj to join her and Hannah in scattering Mack's ashes at the sailing club. Arj notices Ember's camaraderie with Casey, her counselor, whom she just chatted with on the way. Ember brushes it off, but Arj insists he's merely keeping an eye out for her, honoring his promise to Mack.
Down by the bustling waterfront, Hitch and Ember were delving into a mysterious theft, only to catch sight of a youthful schoolgirl exiting Ellis Ashby's car. As Hannah and her cohort, who were also lingering near the waterfront, claimed ignorance of the girl as she belonged to a lower grade, their jaws dropped when, instead of Ellis, it was Brad, the Ashby patriarch, emerging from the vehicle, engaging in a heated exchange with the girl.
Ember hastened to the hospital, seeking Sheena, and warned her that if Miranda had indeed been a victim of abuse, there was a likelihood that the perpetrator would target other innocent girls. Her words were a clear allusion to Brad, and Sheena knew it. But just as she was poised to speak, Brad materialized from behind them, tersely ordering Ember to depart.
Returning to Riz, Ember divulged her concerns, warning that if her informant was indeed the young girl she had witnessed arguing with Brad, she might be in imminent danger. Riz hesitated, wary of the police getting involved before her podcast was released, but Ember swiftly dispelled her fears, revealing her intention to pursue the matter independently, defying her boss's directives.
Riz appeared relieved, confiding that she was struggling to trace the elusive witness who had seen Amy heading towards the lake on the fateful night she disappeared. She confessed that there was no official statement, but merely a photograph of initials, a surname, and a phone number from a caller who had reported what he had witnessed. However, the number was now defunct, and Ember shrewdly pointed out that the initials 'FF' were not conventional initials but police jargon for a 'frequent flyer' - someone who frequently made such reports, hence the lack of follow-up.
Ember and Hitch boldly ventured to the Knightly residence, unbidden by their superiors. Ember relentlessly questioned Mrs. Knightly regarding Amy's disappearance during the weekend, and she affirmed that she had been at a conference while her husband, Russell, was home with Amy. She insisted that Amy had left of her own accord, taking her passport with her, and that no harm had come to her. As Russell joined the discussion, he mentioned Amy's friend Caitlin, though he clarified she wasn't present that fateful night. Amy's parents revealed that there were boys in her life, but they were unknown to them as they came from undesirable backgrounds, and Amy knew they would never approve.
Russell remained vague about the night Amy vanished, claiming he had fallen asleep and thus didn't report her missing until the next morning. As he nervously fidgeted with his hands, Ember inquired about his discomfort, but his wife quickly intervened, explaining that he had been suffering from Japanese knotweed ever since they encountered it. On their way out, Ember's attention was drawn to a photograph of Russell with a former police colleague.
The scene shifted back 17 years, revealing Amy and Caitlin skipping school. Russell, engrossed in a work-related phone call, was unaware of their return. As they sat in Amy's room, discussing her aspirations to travel to far-flung places, Diane, an estate agent, arrived, and Amy explained that their house was being sold. The girls tiptoed downstairs, only to catch Russell and Diane in a compromising position in his office. Undeterred, Amy boldly announced her presence by playing the piano loudly in the hallway.
Back in the present, Ember traced the retired Superintendent from the Knightly's photograph and, posing as a journalist, inquired why the lake had never been searched during Amy's disappearance. He was agitated, explaining that the supposed witness, Mohammed, was a reward hunter who became aggressive when the police refused to take his statement. Armed with this information, Ember realized that Mohammed would have been dealt with under section 89 for his belligerence, and she promptly located him. Mohammed revealed that he had informed the police that he had seen Amy by the lake on a Friday night, contradicting the official report that she went missing on a Saturday. He insisted it was Friday as he didn't work on Saturdays. Furthermore, he recounted seeing a dark car speeding away from the lake two hours after spotting Amy, a revelation that dawned on Ember—Mr. Knightly had lied.
Returning to the Knightly residence, they confronted Russell, who eventually confessed that he had been away that weekend, using his wife's absence as a cover for an affair, leaving Amy alone. He had lied about the date of Amy's disappearance to cover his tracks. He also lied about Amy taking her passport, as he later found it behind the bureau, a fact he had never disclosed to his wife. Ember urged him to confess the truth, as it was about to be revealed. This revelation was significant for Ember, as it now suggested that Mack could have been involved in Amy's disappearance, given the change in the timeline of her disappearance.
Ember desperately pleaded with Riz to view the case file, but Riz confessed that her laptop had been stolen, rendering the file inaccessible even if she had wanted to share it. Worried sick about Mack's involvement in Amy's disappearance, Ember frantically searched for the photograph of them together, but it had seemingly vanished into thin air. She stormed into Hannah's room, unaware that Hannah was with a boy, Kyle, and Ember was in no state to be polite.
"Where's the photo?" Ember demanded, her voice strained. Hannah revealed that it was in her room, explaining that her friend Chloe had been in contact with a podcaster who wanted pictures of Amy, so she had sent them one. Ember was enraged that Hannah had inadvertently informed Riz that Mack knew Amy and she lost her composure. Kyle intervened to defuse the situation, but Ember dismissed him, throwing him out of the house. Hannah screamed that she was going to her grandmother's.
The following day, Ember faced a grilling from her boss, DI Morgan, regarding the Knightly case, which she had been investigating covertly. She pleaded with him to reopen the investigation, but claimed that she didn't want to handle it herself due to her workload, though the real reason was Mack's suspected involvement. As she exited the office, Mr. Ryan, the boat hut owner, appeared, reporting vandalism to his car. Ember took the opportunity to inquire about his private investigator, whom she had caught there a few nights prior, but he denied employing one, and Ember realized it must have been Riz who hired him.
Ember called Riz, leaving a desperate message begging for a call back, revealing that she knew Riz now knew who her husband was. Later, Ember indulged in alcohol, and in flashbacks, we witnessed Amy and Caitlyn at the jetty, where Caitlyn bestowed a St. Christopher necklace on her friend for safe travels.
In the present, Hannah returned home to find her mother drunkenly embarrassed and informed her that Sylvia was outside. Ember quickly regained her composure and let her mother in, requesting a séance to try to contact Mack. However, instead of reaching Mack, Sylvia began to speak of a woman who needed to be found, mentioning that she was in the lake, near the jetty, terrifying Ember.
In another flashback, Amy ventured into a restricted area by the jetty, where men were spraying the ground to eradicate Japanese knotweed. Amy disregarded the warning, flirting with the men in an attempt to provoke Mack, who was working nearby. He became angry with her, scolding her for intruding on his workspace and storming off. Amy was annoyed with Caitlin, who tried to defuse the argument with Mack. In a fit of anger, Amy ripped off the necklace Caitlin had given her and threw it at her before chasing after Mack.
In the present, Hitch messaged Ember, informing her that divers had found something in the lake. She hurried to the jetty as they examined the body, but it wasn't Amy—it was Riz! Who could have possibly killed her?
