Pip returns home on Halloween as her parents take Josh trick-or-treating. Pretending she needs to study and hand out sweets, Pip waits until her family leaves, then urgently texts Ravi to come over.

When Ravi arrives, Pip lays out her suspicion that Elliot Ward is Unknown and may be responsible for Andie’s disappearance, Sal’s death, and Barney’s murder. Pip points out that Elliot had no alibi on the night Andie vanished because Naomi was at Max’s and Cara was at Pip’s, and that Elliot was off work sick on the day Sal died. Ravi struggles with the idea because Sal loved Mr Ward, but Pip argues Elliot had motive if he was the older man Andie was seeing and she threatened to expose him.

Ravi notes that the theory still has gaps, especially how Elliot knew about the hit-and-run blackmail. Pip admits she does not know, but insists Elliot is the person who threatened her and killed Barney. The conversation shifts from identifying Elliot to figuring out how to prove what he has done.

Pip focuses on Elliot’s tutoring schedule, which she now finds suspicious because the Wards do not seem to need extra money and Elliot only began tutoring in 2012. Pip first wonders if Elliot is visiting Andie’s grave, then pushes the idea further: perhaps Andie is alive and Elliot is keeping her somewhere. Remembering Cara’s complaints about food and biscuits disappearing from the Ward house, Pip theorizes that Elliot may be using that food to feed Andie.

Since the next day is one of Elliot’s tutoring days, Pip decides they must find out where Elliot really goes. Instead of following him directly, Pip enables location sharing between Ravi’s phone and her own, planning to leave her phone in Elliot’s car at the end of school. Ravi warns Pip not to go anywhere alone with Elliot.

A knock at the door interrupts them, and Pip answers to a group of trick-or-treaters. As children collect sweets, Pip notices the accompanying adults staring coldly at Ravi and whispering about him, showing that despite the evidence Pip and Ravi have uncovered, the town’s suspicion of Sal’s family still lingers.