The Invisible City by Brian K. Lowe

SPSFC

Captain Charles Clee stumbles onto a secret archaeological expedition from the 23rd century and finds himself stranded nearly one million years in the future. When the woman he loves is kidnapped by one of Earth's alien overlords, he becomes the enemy of one of the most powerful men in the world. But his quest to rescue her is complicated when he learns that a working time machine may still exist with which he could return to his own era and save his troops from certain annihilation. Now, torn between love and his duty to the men who served under him a million years past, pursued by the merciless assassins of the Time Police, Clee fights against war, slavery, and fantastic beasts in a race against time itself--knowing that whatever the outcome, he must lose.

Adult • Science Fiction/Exploration • Science Fiction/Time Travel