Professor Zaroff was a scientist and leader in the field of producing food from the sea. He disappeared in 1950, having presumably been kidnapped and killed, with the Eastern and Western blocs blaming each other. Zaroff in fact had discovered the remains of the lost city of Atlantis and relocated there. He promised King Thous that he would raise his city above the sea, but secretly planned to drain the ocean into Earth's core, with the resulting superheated steam causing the planet to explode. The Doctor defeated his plans and he drowned when his laboratory flooded.