Doctor Mike Olsen returns from his oceanic observation station, where his wife Linda feels in charge, when it's reported in desperate trouble after a sudden shark attack wrecked the oxygen supply. The accompanying ship and even the coast guard are also attacked, and soon other sites in and around the Bermuda triangle, where a few years earlier an alien space-ship crashed, which now seeps a mysterious organic crystal. The US Navy sends a submarine, which also carries bureaucrat Ben Stiles, who berates safety and other violations aboard. More dangers lurk inside as getting out proves physically daunting.