Scientists Banting, Best, Collip and Macleod at the University of Toronto as they race for a treatment to cure 13-year-old Leonard Thompson of his life-threatening diagnosis of diabetes.
as Dr. Frederick Banting
as Leonard Thompson
as Nurse Anna
as Nurse May
as Mr. Thompson
as John Macleod
as James Collip
as Charles Best
as Dr. Walter Campbell
as Little Girl's Mother
as Narrator (voice)