The Last Floor

For twenty years, maintenance chief Sam Kowalski has known the Vantar Biosciences tower better than the people who built it - every duct, every stairwell, every floor he keeps running while Pittsburgh sleeps. Thirty-two stories of glass raised over sealed coal seams, and something far older, waiting in the dark. When the cooling system fails in the sub-basements, that something wakes. It doesn't chase.
It rises - floor by floor, cutting off the exits below, herding whoever is left toward the roof. The company seals the building to protect its secrets. Outside, the city holds its perimeter and will not come in. And Chloe, the daughter Sam has grown apart from, is trapped thirty floors above him. To reach her, Sam has to climb through every level of the tower - and every level of the people inside it, from the panicked cubicles to the executives locking doors to save themselves.
But the higher the survivors run, the closer they come to what has been guiding them all along. Because the way out was never up. A claustrophobic, relentless vertical nightmare for readers who love a story where the building itself becomes the trap.