south across the atlantic "seaview" drives, pausing only long enough for the crew to tap an undersea telephone cable in a failed attempt to get through to the president. then "seaview" charges onward, through the straits of magellan and into the pacific. on their way to the launch point they have to contend with a freshly-laid mine field, a hostile destroyer, an attack sub, and a gargantuan octopus, not to mention an onboard saboteur. nonetheless they reach the launch point in time, thwart the saboteur, and succeed in carrying out their mission. they launch the missile and earth is saved.