Informational film about cancer cells. Shot of a sarcoma cancer cell. Sarcoma starts in the connective tissue. A carcinoma cancer starts in the epithelial tissues. Shot of a yellow legal pad. Drawing appears of buildings and smokestacks and a cigarette pack. Narrator discusses how carcinogens enter the body. Drawing of a person's lungs, person is smoking a cigarette. The lungs turn black as the person inhales. Drawing of invaders and a cell called a macrophasias try to detoxify the invaded tissue. Drawing of carcinogen attacking cells.