Challengers of the Unknown by Jack Kirby #[nn]

In "Chapter Two: Dragon Seed!" from Challengers of the Unknown, the team ventures to a remote tropical island to unlock a mysterious box, only to awaken a legendary stone giant from a hatched "Dragon's Egg." As the creature devastates passing ships and withstands an atom bomb, the Challs face their most overwhelming challenge yet—while Rocky prepares to open the next chamber, the island holds its breath.

In "Chapter Three: The Freezing Sun!", Red returns to the island to confront a chilling mystery: the second chamber is open, and Rocky is frozen solid. With the island under siege by a sentient freezing sun that drains all heat, Red must improvise a vacuum chamber to trap the menace. Meanwhile, Prof, realizing the Dragon Seed Giant can’t be destroyed by force, turns to a different kind of power—thought—while Morelian watches from above, silent and unseen.

In "Chapter Four: The Whirling Weaver!", the Challengers of the Unknown face a spinning, ribbon-wielding machine that threatens to ensnare entire cities. As they track its source, they uncover a hidden dial that halts the chaos—only to find their companion Morelian has already opened the fourth chamber, drawn by greed and a diamond ring promising eternal life. But the ring’s true nature is far more dangerous than he imagined.

When a desperate German scientist named Felix Hesse begs the Challengers of the Unknown for help, he warns them of ULTIVAC—a machine he built, now running amok. With a giant robot hand crashing through the window and snatching him mid-sentence, the team is thrust into a high-stakes chase across the city. Jack Kirby’s dynamic storytelling brings the mystery to life in this thrilling, self-contained adventure.

In "Chapter Three: The Fearful Millions," Jack Kirby crafts a pulse-pounding tale of suspense and scale, as the captured robot ULTIVAC—displayed before thousands in Yankee Stadium—sends a desperate mental call to June. With Ace in a jet and Prof diving into the depths, the stakes rise as ULTIVAC escapes beneath the sea, dragging June into an underwater mystery that tests the limits of courage and ingenuity.

In "Chapter Four: The Fatal Prediction!", the Challengers of the Unknown face a chilling twist when the seemingly defeated ULTIVAC reveals a shocking deception—its destruction was a ruse. As tensions rise and lives hang in the balance, June's plea for peace forces the machine to confront its role in humanity’s future, leading to a moment that tests both trust and fate. With lives lost and hearts broken, the team must decide how far they’ll go to protect the world—and what it truly means to be a hero.

In "The Day the Earth Blew Up," the Challengers of the Unknown are called to investigate a pair of vanished scientists in Antarctica, leading them from the Pentagon to icy tundras and a sudden volcanic eruption off New Guinea. As Ace, Rocky, and Red race to uncover the truth, they're split apart—falling through thin ice, discovering a hidden bridge, and confronting strange orange aliens in bubble-suits—while the planet itself seems to be unraveling.

In "Chapter Two: The Tyrans," the Challengers of the Unknown—Ace, Rocky, and Prof—find themselves trapped in a vast, alien-engineered shaft beneath the Earth, navigating a labyrinthine airshaft that leads to a hidden underground city. There, they discover a civilization preparing a global assault, using hidden charges to destabilize the planet, and must outthink their alien captors before the invasion begins.

In "Chapter Three: The Thing That Came Out of the Sea," the Challengers of the Unknown face a terrifying alien threat as they battle a gravity-warping machine beneath the ocean floor. With Ace and Rocky racing against time to destroy the main detonator, Prof and Red rush to alert the military while a mysterious claw-machine erupts from the Pacific to attack the Navy.

In "Chapter Four: One Minute to Doom," Jack Kirby delivers a pulse-pounding rush as the Challengers of the Unknown face a deadly alien threat on a remote Pacific island. With time running out and a corrosive gas spreading, Ace and the team must outthink the enemy before it's too late—while Prof pays the price for a cold caught in the most unexpected place.

In "The Menace of the Ancient Vials! Chapter 1," Karnak and his crew crash-land on a remote island during their escape from the Challengers, only to stumble upon Amos Hunter and five enigmatic vials. When the first vial is opened, it triggers a sudden, terrifying transformation—two of the gang members grow into towering giants.

In "The Traitorous Challenger," the Challengers of the Unknown face an unstoppable, one-eyed, box-like creature that leaves destruction in its wake—until Prof realizes its solar-powered eye holds the key to stopping it. As the team races against time, June’s strange actions raise questions, but her hidden calculations ultimately shift the outcome in their favor.

In "The Monster Maker," the Challengers of the Unknown face off against the ambitious Roc, who wields mind-over-matter to summon a giant ape and launch a missile. When the tide turns, the team’s scientist ally unlocks similar powers in Ace, leading to a surreal clash of imagined beasts—dragons, knights, and even a giant vacuum cleaner—before Ace uses spinning circles to outwit Roc in a mind-bending showdown.

In "The Secret of the Sorcerer's Mirror," the Challengers of the Unknown race against Hillary Mycroft and his gang to recover a mystical mirror and chart stolen from a museum—artifacts tied to ancient secrets hidden beneath the sea, atop a stone needle, and on Sinbad's Island. With the mirror revealing three perilous locations, the team splits up, each facing dangerous trials in their quest to stop Mycroft from assembling the globes that could summon a genie, while Red secretly works to dismantle the threat from within.

In "The Menace of the Invincible Challenger," the Challengers of the Unknown are drawn into a bizarre experiment when a monkey enhanced by a meteorite-derived pill is launched into space—only for Rocky to take the same pill and rocket into orbit, emerging with terrifying powers and a fractured mind. As the Challs and June track down the unstable hero, they face a dangerous crook who’s exploiting Rocky’s strength, unaware that a single bullet graze might be the key to reclaiming his mind.

In "The Wizard of Time, Chapter 1" from *Challengers of the Unknown*, the team is pulled into a mystery when a group of men in ancient Greek garb try to steal a plane—only one is captured, begging to return to the "Island of the Wizard." Led by the enigmatic Darius Tiko, a scientist obsessed with time travel, the island holds a secret in the form of a time cube. When Tiko vanishes into one, the Challengers and the captured soldier leap after him, chasing the past through shifting timelines.

In "Chapter II: The Men Who Rode Across the Sun," Ace and Rocky split up in ancient Greece, where they're swiftly branded as ill-omened messengers by a wary oracle. Forced to flee the enraged locals, they track down Tiko's stolen plane, crash-land it near a forgotten ruin, and hope their missing teammates—Prof and Red—will return in time with the time cube.

In the sands of Egypt, Prof and Red confront the aftermath of Tiko’s theft, destroying the stolen telescope before reuniting with Rocky and Ace. With the past now a mystery, the team sets off through time to the 15th century, chasing whispers of Nostradamus and the elusive Tiko—just as the seer’s shadowed path begins to unfold.

In "Chapter IV: The Mechanical Judge," the Challengers of the Unknown stumble upon Tiko in a distant future, only to be arrested and put on trial before a cold, unfeeling machine. The verdict is swift—charges dismissed—but the real test lies ahead as the team is sent back in time, trapped in a single cube, with Tiko’s fate hanging in the balance.

In "The Riddle of the Star-Stone, Chapter One," Professor Brandon’s assistant Vreedl steals the ancient Star-Stone and begins a dangerous quest to power it with stolen gems—first transforming into a flaming being to create chaos and buy time, all while the Challengers of the Unknown close in. Jack Kirby’s bold art and storytelling bring a classic sci-fi mystery to life, where every gem could unlock a new threat.

In "Chapter Three: The Challenge of the Super Creature!", the Challengers of the Unknown face off against Vreedl, who gains bizarre powers from a mysterious gem—first turning into a fish man, then becoming seemingly invincible. As the stakes rise, Ace confronts Vreedl with a sobering truth about the gem’s power, leading to a moment of reckoning that changes everything.

In "Captives of the Space Circus," the Challengers of the Unknown respond to a distress call only to be ensnared by a bizarre space circus, where they’re forced into gladiatorial combat against the monstrous Quadro, the Four-Finned Demons. Trapped among other alien captives and pitted against their captors in a high-stakes spectacle, the team must find a way to survive—until Prof discovers the strange atmosphere grants them super-strength, turning the tide in their favor.

When pilot June Robbins crash-lands on a mysterious island, she stumbles upon an ancient lamp that awakens forces beyond her control. The Challengers of the Unknown follow her trail to a hidden valley, only to be ambushed by unseen magic and discover June transformed—her will bound by the sinister Charles Agar, who has turned the forbidden valley into his own dark domain.

When a mysterious crash site draws the Challengers of the Unknown to a remote location, they uncover a hidden spaceship—and three alien creatures trapped inside. With time running short, the team must decide how far they’re willing to go to return the beasts to their confinement, even if it means facing the consequences of their choice.

In "The Isle of No Return," the Challengers of the Unknown team up with honorary member June Robbins to track down a burglar who can walk through walls. When their pursuit leads them to an abandoned lab once owned by the reclusive Prof. Macon, they find themselves trapped by a shrinking ray—but June’s quick thinking may be the key to turning the tide.