A massive thunderstorm in Manhattan is revealed to have been caused by a Martian fiend named Bolton. Mars, apparently a planet of warriors, is hoping to extend its dominance, and Mars himself personally appoints Bolton to take on the conquest of Earth. Bolton turns himself into a meteor & heads for Earth. While this is happening Spidey interrupts 2 thieves trying to rob a safe, one of whom is known as 'Boomer'. Spidey cuts off the thief during his getaway, and seconds later Bolton appears. The web-slinger brings down Bolton and ties him up with some help from a group of hot-rodders, but Boomer cuts the giant loose. Bolton counterattacks Spidey with a lightning bolt intended to send him into space, then moves off with Boomer to rob a gold depository as the military tries, unsuccessfully, to stop the giant Martian. Spidey escapes Bolton's trap and knocks down the giant again. Enraged, Bolton hurls lightning bolt after lightning bolt at Spidey but misses. The giant then throws an apparently indestructible bolt at the web-slinger, who tricks it into catching Bolton himself & launching the giant into space, back to Mars. Spidey uses Boomer's amazement as a chance to catch him, and knocks the thief unconscious to await the arrival of police.