Callsign: King II- Underworld (Chesspocalypse Series #4)

Strange things have always happened in the Superstition Mountains of Arizona…Bizarre lights, reports of cave entrances that appear and then vanish, hundreds of mysterious disappearances…and rumors of monstrous creatures that inhabit a labyrinthine underworld.

When a terrifying accident on an Arizona highway leads to a military exclusion zone and a cover-up of staggering proportions, Jack Sigler-Callsign: King, field leader of the elite and ultra-secret covert Chess Team-joined by his closest friend, archaeologist George Pierce, sets out into the desert, intent on discovering the truth.

Assisted by a beautiful paranormal investigator, dogged by soldiers intent on preserving the quarantine, and pursued by a relentless legendary hitman, King soon finds himself in a race against time to prevent all out war with the creatures that inhabit the underworld.