A plane crash. A missing memory. A countdown to darkness.

After a plane crashes into the icy waters near the remote Alaskan town of Midnight Harbor, former Navy SEAL Josh Black pulls a lone survivor from the wreckage. He knows her as Sarah Samson, a local waitress. But the woman who wakes in the hospital knows her real name is Amanda—and has no memory of how she ended up aboard the doomed flight in an evening gown. All she knows is the terrifying warning she uttered before losing consciousness: Dark Goodbye is coming.

As fragments of her memory return, Amanda realizes Dark Goodbye is connected to the cybersecurity project she helped develop—and to Heath, the powerful ex-husband holding her critically ill mother hostage. What Amanda thought was legitimate security work has become part of a coordinated attack capable of collapsing the nation's power grid. Heath's men are after her, even as the first failures have already begun.

With Alaska descending into chaos and outages spreading across the country, Josh and Amanda must survive the wilderness, outrun the people hunting them, and uncover a way to stop Dark Goodbye before the entire grid collapses. But Amanda can't escape the role she played in creating the catastrophe—and stopping it may be her only chance to prove that failure doesn't have to be final.