When quiet Year 10 student Cassie Turner accuses Amy, Siobhan and, later, Michaela of bullying her, it looks like the girl gang problem has returned to Waterloo Road, as the school drama continues. Despite the protests of innocence from the accused girls, however, Cassie's recent detached behaviour, along with her falling grades, is enough for Kim to haul the suspected offenders off to the Cooler. Cassie's best friends, Lauren and Sam, are hurt that she didn't go to them for help, but also believe she is being bullied.
Cassie's mother has a meeting with Kim and seems relieved to find that bullying is the cause of Cassie's recent strange behaviour. During one of Ruby's lessons, Cassie flees the room terrified – grabbing Karla and harming herself while cowering in the boiler room. Cassie is rushed to hospital and, although she is physically fine, the doctors suspect the onset of a psychological disorder.
Helen's management of the pupils' behaviour, meanwhile, is more lax than ever. When Michaela discovers Helen's address via a social networking site, a gang of Waterloo Road teens turn up and wreck her flat. Desperate for help, Helen rings Tom, who rushes to her aid but leaves Helen seriously considering her future at the school.
Meanwhile, Rachel struggles to keep Max's marriage a secret from Kim. When Rachel finally tells her the truth, Kim dumps him on the spot. Later, Max storms round to Rachel's flat, furious that she told Kim he was married. When Rachel tries to shut him out, Max pushes her and only relents when Rachel threatens to call the police.