Charon: A Dragon at the Gate

Aliens are spying on Earth from one of the four worlds that make up the Warden Diamond. But it is impossible to send agents to any of the four worlds because of unique microscopic symbionts that make it impossible for visitors to leave the Diamond.

Seeking a unique solution, each of the four worlds making up the Diamond is sent a person whose mind has ben stripped of everything and who is now controlled by an agent of the Confederacy.

Park Lacoch's body (stripped of his own mind) is exiled to the hell-world of Charon, one of the Warden Diamond worlds being investigated for alien influences and presence. Can he survive long enough to complete his investigation in this unbearably hot world where strange creatures roam and witchcraft is a normal way of life?

This is the third book of the Four Lords of the Diamond series. The others are:

Lilith: A Snake in the Grass
Cerberus: A Wolf in the Fold
Medusa: A Tiger by the Tail