The Darkest Day. (Victor the Assassin 5)

He is darkness. She wants him dead. In a city starved of light, she might just succeed. She moves like a shadow; she kills silently: Raven. This elegant assassin has been on the run for years. This time though, she has picked the wrong target. The hitman known only as 'Victor' is as paranoid as he is merciless, and is no stranger to being hunted. He tracks his would-be killer across the globe, aiming not only to neutralise the threat, but to discover who wants him dead.
The trail leads to New York... And then the lights go out. Over twelve hours of unremitting darkness, Manhattan dissolves into chaos. Amid looting, conspiracy and blackout, Victor and Raven play a vicious game of cat and mouse that the city will never forget.