New recruit PC Nate Roberts, a seasoned professional with an appetite for action and an eye for the ladies, joins his colleagues in crowd control outside a crack den that has been set on fire. Meanwhile, Phil clears his desk and prepares to move on, convinced none of his Sun Hill colleagues except Sam will give him a second thought. Diane is shocked to encounter an old army pal living in a squat with his girlfriend, who has been injured in the crack den fire. She and Callum investigate the pair's involvement in the fire.