Rob, unmoored by Cassie's absence, is increasingly obsessed with Jonathan Devlin, convinced he and his childhood friend Cathal Mills may be dangerous paedophiles. He is desperate to find the one witness to the events in the woods in 1985 that he hasn't yet spoken to - itinerate ex-friend of Jonathan and Cathal's, Shane Waters. But Shane, a homeless drug addict, hasn't been seen since Katy's body was found.Meanwhile, Jonathan has sent his daughters Rosalind and Jessica away from Dublin. Rob tracks Rosalind down to a dingy caravan park. Soon the extent of Rosalind's disturbed behaviour emerges, and Rob feels he can save the girl. Meanwhile, Cassie starts to back away from Operation Vestal, spending time with Frank as he schools her in the art of being Lexie.Rob realizes time is running out on the investigation and decides the only way to fully remember what happened that day is to spend the night alone in the woods, totally immersed in that strange world...