Ten years ago, six-year-old Catalina Mateo hid under the porch of her family home while a knife butchered her mother and a bullet killed her father. Now a rough-sleeping orphan, Cat arrives at the house of Detective Jonathan Stride, pleading for protection. Drenched in the icy waters of Lake Superior, she claims to have narrowly escaped a cold-blooded killer.

Stride's raw instinct is to protect Cat, whose late parents' case—and his personal guilt associated with it—still sends a shiver down his spine. As a result, he takes the troubled teenager under his wing.

But Stride's partner, Maggie Bei, is not convinced. She doubts the sincerity of this beautiful young streetwalker who has so easily won Stride's trust, and now sleeps in his house with a butcher's knife under her pillow.

As Stride continues to care for Cat, Maggie's suspicions solidify, and a single question occupies the void between them: Should Stride be afraid for, or of, this terribly damaged girl?