Peter Watson is troubled with pain and and an inability to sleep. He tries to light the gas-fire and seeks held from another lodger, artist Nicholas, who is spending the night with his model and is reluctant to be disturbed. Another neighbor, Pollen, tries to be helpful but is hit by Watson. Frightened and angry, Pollen calls for police help. The others in the boarding house are awaken by this time, and Mrs. Harris tries to help the mentally confused Watson but he also refuses her help. The police clash with Dr. Sanderson, a welfare worker, who thinks he can take the gun-toting Watson without complications, but when a police sergeant is injured, Police Inspector Thompsonis determined to take Watson by force if necessary.