The Monk's Grimoire - The Veritas Codex Series, #4

The Devil is on the march and only one woman has the power to stop him-if she makes an unbearable sacrifice. Television investigator Lauren Grayson's life is shattered when a Prague professor discovers an ancient document known as the Devil's Codex-with Lauren's name embedded in the text. She's forced to travel to Europe, where she's abducted, drugged, grilled, and threatened. A string of gruesome murders terrify the city, and police consider Lauren the prime suspect.
Ancient texts reveal a supernatural plan to raise an army from Hell to conquer the world. Lauren searches for the key to preventing an apocalypse in the Monk's Grimoire, only to find critical pages have been removed. In the midst of the unearthly chaos, Lauren's arcane powers intensify, at the same time that her young son Henry also exhibits strange abilities. Lauren is faced with the impossible burden of solving the murders, clearing her name, and stopping the devil himself-while a prophecy foretells that she will be forced to make a terrible sacrifice. If you like supernatural suspense, pulse-pounding action, relentless twists and turns, and Old World mythology brought to life, you'll love The Monk's Grimoire.