During the Blitz, the Doctor and Rose arrive in London while pursuing a metal cylinder through the Time Vortex. A small boy wearing a gas mask asks Rose repeatedly if she is his mother as she pursues him. She is saved by Captain Jack Harkness (a former Time Agent who is now a scam artist), who entices her to purchase a priceless warship after she climbs a rope linked to a barrage balloon that soars into the skies. Nancy, a young woman who knows the boy is linked to a bomb-like device that recently fell, speaks with the doctor. She leads the doctor to a hospital, where Dr. Constantine shows him gas masks that are just like the boy’s and patients who have been injured. Nancy identifies the youngster as Jamie, her brother. As Constantine starts to change like his patients, Rose and Jack show there just in time to save the Doctor.