A serial in four episodes by Evelyn Frazer and Vincent Tilsley.
Starring Robert Harris and William Greene
with Alan Gifford, Mark Dignam, Helen Lindsay, Clive Morton, George Pravda
and introducing Elizabeth Weaver
Why did Professor Cato have a miniature submarine? Why did he use it to make the police think there was a 'monster' in Lake Kingswater? And what went wrong? Do the monsters really exist after all? Tonight John Brent finds out some of the answers.
