Grimes, an amoral chimney sweep, occasionally likes to steal valuables from his clients. One day, on the verge of being caught, he frames his young apprentice, Tom, for the crime. Tom runs away and jumps into a river where, instead of drowning, he finds himself transformed into a mystical aquatic creature. Swimming and breathing effortlessly, he discovers a colorful underwater world replete with creatures both cruel and kind.
James Mason
Bernard Cribbins
Billie Whitelaw
Tommy Pender
Samantha Gates
Joan Greenwood
David Tomlinson
Jon Pertwee
David Jason
Una Stubbs