James Tiptree, Jr. Award winner (2004). Nebula Award winner (2005).
The artifact is found seven miles below the surface of the sea and
beneath forty more feet of sand. The Navy's efforts to raise a wrecked
submarine uncover it – and set in motion a scientific race to retrieve
it, to discover just what it is and where it came from. Denser than any
substance known to man, it has broken every drill bit they've tried on
it and will not budge an inch. It resists every effort to breach it –
or communicate with it. So the government turns to marine biologist
Russell Sutton for help.
Meanwhile, unknown to any of them, two creatures have wandered the
earth for generations. The aliens have no knowledge of each other, but
possess a residual memory of the artifact – and an affinity for deep
water. One, which calls itself the changeling, has survived by
adaptation, by taking on many different forms: man, woman, snake,
shark. The other, which calls itself the chameleon, has survived solely
by destroying anything or anyone that threatens it.
Now, finally brought up from the bottom of the sea, the
artifact calls them both... to come home. For all these generations
there have been two invincible creatures on Earth. But the chameleon
has decided there's only room for one.