Thor, trapped at the center of the
planet Phantus, is stuck between time and Limbo, resulting in half
his body reverting to that of Dr Donald Blake. And the Space Phantom,
who tricked him there, finds that Thor's divine powers are decreasing
and he is not reversing the planet's slide into Limbo as the villain
had planned. SP is forced to teleport Thor out of the vortex and
bargain with him, offering the return of Mjolnir for Thor's help in
saving the planet. The two travel to the edge of the world and into
Limbo to find the castle of Immortus, whom Thor believes has died (in
AVENGERS #142), looking like a test doodle for an M.C. Escher print.
Entering the castle, they face Tempus, Keeper of the Castle, who
resembles a Frost Giant (according to Thor). Thor and Tempus battle,
the former finding it hard to fight without his hammer and the latter
learning that most of his attacks don't work against a god. Thor
eventually seizes his foe's weapon, a giant club of stone, and uses
it to knock Tempus' head off. But he won't stay dead for long so SP
hurries Thor along through rooms and halls where gravity and time are
meaningless and into the throne room of Immortus. The villain trades
Mjolnir for Tempus' club, explaining that he only borrowed it so he
could examine its time travel properties. In return, Immortus
explains how he is still around even though both he and his earlier
incarnation Kang have died. This explanation ranges over several
comic appearances and, as Thor says, mystifies as much as enlightens.
Space Phantom reminds Thor of his promise to help his world so Thor,
warned by Immortus that this action will deplete Mjolnir's time
powers, gladly makes the sacrifice to push Phantus back into its
normal position. Immortus sends Thor back to Earth, leaving the God
of Thunder to wonder if this was all a contrivance to strip his
hammer of its time properties. Nevertheless, he is ready to face the
challenge of the Celestials, like a god!