THIS HOSTAGE EARTH!

When Giant-Man and the Wasp take a rare break from Avengers business to work in Henry Pym's laboratory, their quiet afternoon is interrupted by a cybernetic distress signal transmitted through Pym's ant communication helmet. The terrified ants cannot clearly explain the danger, but their panic convinces Giant-Man that a grave threat lies beneath the surface. Ignoring the Wasp's skepticism, he immediately summons the Avengers to an emergency meeting.

At Avengers Mansion, Giant-Man explains that the alarm came from a colony of ants. Iron Man and Thor openly mock the idea of assembling Earth's Mightiest Heroes over an ant hill, believing the emergency to be ridiculous. Giant-Man reminds them that his ants have never issued a false warning and points to previous subterranean dangers, such as the Mole Man, as proof they should investigate. Thor dismisses the possibility that the Mole Man could still be alive, insisting he perished during his battle with the Fantastic Four. Frustrated by the ridicule and unwilling to beg for assistance, Giant-Man angrily leaves to investigate alone while the other Avengers allow him to storm off.

Deep beneath the Earth's surface, the Mole Man has secretly rebuilt his underground empire following his apparent defeat. Driven by revenge against the surface world, he unveils his greatest weapon—an enormous atomic gyroscope capable of accelerating the Earth's rotation. As the planet spins faster and faster, all life on the surface will be destroyed while the Mole Man's underground civilization survives within an artificially maintained gravitational field. Because ants are especially sensitive to subtle changes beneath the Earth's crust, they are the first creatures to detect the disturbance, prompting the warning that reached Giant-Man.

Refusing to wait for help, Giant-Man shrinks to insect size and enters the disturbed ant hill alone. The Wasp declines to accompany him, choosing to keep an appointment at her hairdresser instead. As Giant-Man explores the tunnels, violent tremors suddenly cause the entire ant colony to collapse around him. Reacting quickly, he enlarges himself to stop his fall into an immense underground chasm before cautiously descending to its depths. There he discovers strange defensive energy barriers surrounding a hidden subterranean complex, confirming that an enormous secret installation lies below the surface.

The Mole Man detects the intruder using his extraordinary radar-like senses and dispatches an army of subterraneans to eliminate him. Giant-Man easily brushes aside the primitive warriors despite their advanced weapons, using enormous slabs of stone as shields while trying to avoid seriously harming his attackers. However, the Mole Man surprises him with a powerful stun gun blast, rendering Giant-Man unconscious. The captured Avenger is securely restrained with specialized cables and imprisoned inside the Mole Man's underground fortress while the villain celebrates the symbolic conquest of one of Earth's greatest heroes.

As the atomic gyroscope gradually increases the Earth's rotational speed, strange disturbances begin occurring across the globe. Buildings sway unnaturally, seismographs register impossible readings, famous landmarks begin shifting, and bridges tremble dangerously. Only then do the remaining Avengers realize Giant-Man had been telling the truth. Filled with remorse for mocking their teammate, they resolve to rescue him and uncover the source of the growing catastrophe.

The Wasp uses Tony Stark's experimental image projector, which creates a remote, intangible duplicate of herself capable of traveling immense distances. Following Giant-Man's cybernetic signals, her projected image reaches the Mole Man's underground kingdom and discovers that Giant-Man has indeed been captured. Although the projection cannot physically interfere, it provides the Avengers with the crucial information they need before safely returning to headquarters. Unfortunately, the Mole Man realizes someone has located his base and immediately orders a squad of subterraneans to attack the surface.

The subterranean strike force suddenly attacks Avengers Mansion using unusual energy weapons, magnetic devices, poisonous gases, and flamethrowers. Captain America, Thor, Iron Man, and the Wasp battle the invaders while Rick Jones assists where he can. Despite the enemies' advanced weaponry, the Avengers work together effectively, rescuing one another whenever necessary and ultimately defeating the attackers without inflicting unnecessary casualties. Before they can interrogate the prisoners, however, a mysterious cloud envelops the subterraneans, allowing them to disappear.

To reach the center of the Earth, Iron Man modifies Stark Industries' powerful transistorized digging machines into a massive underground boring vehicle. Captain America and Rick Jones retrieve critical electronic components from a Stark warehouse, where they interrupt a gang of thieves stealing valuable equipment. Although Captain America is briefly stunned by the powerful criminal known as Monk, he quickly recovers, defeats the gang, reassures a discouraged Rick Jones, and delivers the necessary equipment so Iron Man can complete the vehicle. Thor then uses Mjolnir to locate the exact point where the Avengers should begin their descent.

Meanwhile, far below, the Mole Man unexpectedly gains a powerful ally when the Red Ghost arrives. Having developed the ability to render both himself and others intangible, the former Soviet scientist proposes an alliance. Believing their combined powers will make them unstoppable, the Mole Man agrees to the partnership just as alarms signal the approaching Avengers.

The Avengers reach the Mole Man's hidden kingdom and immediately encounter deadly defensive energy barriers and the Red Ghost's devastating energy weapon. While Iron Man counters the Red Ghost's attacks, Thor and Captain America battle through the fortress. Elsewhere, the Wasp locates the imprisoned Giant-Man and learns he is being held within an anti-cybernetic energy field. Following his instructions, she forces open the heavy control switch that deactivates the prison, allowing Giant-Man to regain his freedom. Together they race to rejoin their teammates.

As the Mole Man prepares to launch hyper-ionic rockets against the Avengers, Thor hurls them harmlessly back toward their source. The Red Ghost renders both himself and the Mole Man intangible, allowing the missiles to pass through them unharmed. Believing victory to be certain, the Mole Man reveals the atomic gyroscope responsible for Earth's increasingly violent upheavals and boasts that he can destroy all life unless humanity surrenders to his rule.

Unknown to the villains, Giant-Man secretly shrinks to ant size and slips inside the immense atomic gyroscope. Using his scientific expertise, he rewires its intricate circuitry, creating a cascade of short circuits that permanently disables the machine. As the Earth's rotation returns to normal, Giant-Man resumes his giant stature and rejoins the battle. Although the Red Ghost and Mole Man escape immediate capture by becoming intangible, Thor uses Mjolnir to trigger a massive cave-in that buries their military installations beneath tons of rock. Iron Man seals the escape tunnels behind the retreating Avengers, trapping the villains underground and ending their immediate threat.

Back on the surface, newspapers celebrate the Avengers' victory and the world unknowingly escapes global destruction. The Wasp cheerfully suggests the team owes Giant-Man both an apology and a vote of thanks for believing his warning when no one else would. Deep beneath the Earth, however, the defeated Mole Man and the Red Ghost blame one another for their failure, proving that even their new alliance cannot survive defeat.