It is Will Hoffman's first day in UNIT, and he is assigned to drive Colonel Chaudry to a Code Blue. Meanwhile, several people in the area have become infected with the Darkness, attacking their friends and family. Will and the Colonel arrive at a blue police box, which the Colonel states is the Code Blue. A man is being mugged by a teenager, and they rescue him. The Colonel introduces him as the Doctor, UNIT's former science advisor. The Colonel calls in several floodlighting rigs, lighting up the street. The Doctor can detect no trace of it.