Down Below & the Archon's Castle (A Couple Through Time, #1)

When Tod vanishes into another world, Zoe follows, determined to find her lost friend. But she soon discovers she's entered a universe unlike any other—one where a floating Sphere, a shape-shifting Rubbery Man, and a formidable Rock Man become her unlikely allies. Their search for Tod leads them through landscapes of wonder and peril: a world of Ancient Stone Ones, a planet ruled by women, and a castle where a mad scientist bends reality to his will.

This is the beginning of an epic, eight-p...