Their creators designed them to be the perfect weapons.

They forgot to make sure they could control their creations.

Sparrow's explosive powers make her a living bomb. She spends her life locked away in a fireproof cell, brought out only when something needs to burn. But the longer you contain an explosion, the stronger it becomes.

All she knows is that she wanted to see the sky. Then came fire, and screaming, and death. Now she's lost on unfamiliar city streets, hunted by her creators and the civilian authorities alike.

Mary went from being a failed experiment to a lab assistant prized for her intelligence and her perfect obedience. But after years without useful results, her lab is slated for shutdown. That means the dissection table for Mary. Unless she captures her creators' rogue weapon and proves her lab holds the secret to controlling her power.

Mary offers Sparrow the thing she thought she could never have: freedom. Freedom from her creators, and from her own uncontrollable power.

It's a lie.

Mary accepted long ago that there's no such thing as freedom for people like them. There is only survival—and she'll do whatever it takes to survive.