A group of 21st-century colonists inhabit an underwater city called Pacifica. Originally intended as a purely scientific installation, the U. S. government wants to stash all its gold reserves from Fort Knox there, along with a fantastic new radioactive element. The brother of Pacifica's returning former commander plans to steal the gold and on top of that, the city faces destruction by an asteroid from outer space!

美国海军上校尼尔逊（沃尔特皮金饰）领导潜艇海景号在北极下探测时，地球突生危机，大气层被一股大火燃烧，令地球极速升温，地球上干旱无雨，顿诚人间炼狱。科学家主张纷歧，尼尔逊决定由海景号发射核子飞弹，让其在大气层外爆炸以期熄灭大火，令地球降温。为求能够快速解决这个问题，尼尔逊毅然由船员自愿选择是留在船上还是继续前进，但是在全世界都没有办法的情况下，只有听命于尼尔逊的这个计划了……