Lionel Jeffries directs and co-writes this live action and animated feature based on Charles Kingsley's novel. 12-year-old Tom (Tommy Pender) is an amiable young lad apprenticed to the dishonest Master Chimney Sweep Grimes (James Mason). When the boy is falsely accused of stealing, he escapes his pursuers by running away and jumping into Dead Man's Pool. Under the water's surface, he is transported to an animated world and finds himself having to rescue some new friends. After discovering this amazing new world and getting caught up in its adventures, will he ever get to return back home? The cast also includes Billie Whitelaw, David Tomlinson, David Jason, Jon Pertwee and Una Stubbs.