A scientist experimenting with plant life on a remote island has run into trouble. A shore party from Seaview arrives only in time to hear his dying warning that the world will be taken over in eight hours. Nelson brings aboard the only unusual thing he can find -- a red orchid, which proves to be a malign alien (that proceeds to take over his mind and those of the crew).
Elenco: Richard Basehart , David Hedison , Robert Duvall , Terry Becker , Del Monroe , Paul Trinka , Richard Bull , Robert Dowdell .