Bullied at school and ignored and abused at home by his indifferent mother and older brother, Billy Casper (David Bradley), a 15-year-old working-class Yorkshire boy, tames and trains his pet kestrel falcon whom he names Kes. Helped and encouraged by his English teacher Mr. Farthing (Colin Welland) and his fellow students, Billy finally finds a positive purpose to his unhappy existence, until tragedy strikes.
