Jack: Lock The Doors. Watch The Roof.

JACK

Lock the doors. Watch the roof.

For thirty years, Calder dismissed Jumping Jack as an urban legend-a masked figure glimpsed on rooftops, a warning whispered after dark.

Then building inspector Nora Keene finds evidence of someone moving through the forgotten spaces above the city.

When a routine inspection turns deadly, Nora discovers that locked doors offer little protection from a killer who knows the buildings better than the people inside them. He climbs where no one thinks to look. He enters where no one believes a person could fit. And three quiet knocks can be the only warning he gives.

As the body count rises, Nora joins forces with a woman who survived Jack decades earlier. Together, they uncover a history of hidden rooms, ignored warnings and a man who was never a ghost.

Now Jack knows Nora's name.

And he's coming down from the roof.