Despite the angry scars she carries from her childhood training, Zoe Lorel has reached a good place in her life. She has her dream job as an elite operative in an international spy agency and she's found her one true love. Her world is mostly perfect—until she is sent to abduct a nine-year-old girl.

The girl is the only one who knows the riddle that holds the code to unleash the most lethal weapon on earth—the first ever "invisibility" nanoweapon, a cloaking spider bot. But Zoe's agency isn't the only one after the child. And when enemies reveal the invisibility weapon's existence to underground arms dealers, every government and terrorist organization in the world want to find that little girl.

Zoe races to save not only the child she has grown to care about, but also herself. The agency prescribed pills—the ones that transform her into the icy killer she must become to survive—are beginning to threaten her engagement to the one person who brings her happiness. Can she protect the young girl and still protect the one thing she cares more about than anything else?