Nikki and Jack are under pressure when a teenager's remains halt an eco-housing project, while Leo is trapped in a dangerous hospital siege as distraught Tom Hancock holds a ward at gunpoint to turn off his terminally ill son's life support. Leo agrees to do his son's post-mortem to diffuse the situation, and becomes embroiled in Tom's quest for the truth behind his son's cancerous tumours.
When Leo discovers that Tom's son had the same kidney disorder as the housing project victim, he suspects a dangerous local health hazard. Far from convinced, Nikki enjoys a whirlwind romance with charismatic science minister James Embleton, the eco-housing project owner, despite his belligerent father's discomfort. New construction site evidence leads Jack to builder Brian Blackburn, with suspicion falling on his son, who has sudden behavioural problems. And as Leo's investigation into a health hazard hits another barrier, he becomes convinced he is onto a cover up.