A group of sixth form students on a weekend retreat at a leisure centre bear witness to a man on fire who falls from a cliff into the river below. The victim, Gideon Frane, is discovered to have been a former head boy at a local boarding school for high achieving students but is also known to have a chequered past, having been responsible for 97 incidents of harassment against his ex-girlfriend. When Billy discovers the cause of death was poisoning, Vera begins to look at the case from a completely different perspective. When the team finally track down Gideon's former best friend, Jamie Levinson, both he and Vera fall victim to further poisoning. Connections start to build when Joe links the case to the death of a former teacher at their school, whose daughter happened to be present when Gideon was murdered.
