New boy Finn's disruptive behaviour continues at Waterloo Road and he persuades Josh and Amy to join him in smoking a legal high. For Amy, it's a far-from-pleasant experience and Josh has further side-effects when he starts hallucinating in class. Tom, worried about his son's behaviour, questions Josh who "fesses" up - believing that his dad would be cool about it as they are more like friends than father and son. However, Josh is stunned and humiliated by Tom's angry reaction and, in retaliation, he spikes Tom's lunch with the drug.