Ragnarok is the fourth full-length novel in the Jack Sigler/Chess Team series, following Pulse, Instinct and Threshold, as well as the prequel novel Prime, and eight standalone novellas focusing on the individual characters in the series. It starts with a thunderous crack and a flash of light. Screams come next. Then the hunters. With a staccato flicker, the light disappears and everything within a hundred yard radius...