Adversary. Shadows of the Past, #1

Haunted by the violent death of his wife, Washington, D. C. homicide detective Sam Hardin struggles with his relationship with his two children, and the bottle. Called to investigate a murder he discovers a connection to an alleged mob boss, and the theft of an ancient artifact discovered in Antarctica. The artifact, a knife, contains an alien power that affects anyone who comes into contact with it.
Jack Griffith served his country in the middle east, losing a leg in the process, and was recently diagnosed with cancer. While clearing a clogged sewer drain he is stabbed by the stolen knife and becomes possessed by an ancient entity that seeks to end the rule of man. His transformation leads him on a violent rampage. His fury focused on a brain damaged four-year-old he believes is the embodiment of his old adversary who holds the secrets of the universe.
The boy's death could open the passageway between the shadows of the past and present day, allowing old gods to rise to power once again. The only thing standing in his way is Sam Hardin. Guilt, redemption, and the supernatural weave together as Sam and Jack's paths converge in a climactic showdown from which only one of them will survive.