Self-taught tinkerer Kali McAlister is determined to build an airship and escape the frigid Yukon forever. Unfortunately, she’s the heir to the secrets of flash gold, an alchemical energy source that tends to make her a popular target for bandits, gangsters, and pirates.

With the help of her bounty-hunting business partner, Cedar, Kali has outwitted and eluded attackers before, and she thinks she’s prepared for anything. Then her ex-fiancé strolls into her workshop.

As if fooling her once wasn’t enough, he aims to embroil her in a fresh scheme. Meanwhile, a new nemesis is stalking her, a shrouded figure with an arsenal of deadly machines that make Kali’s inventions seem like toys. This time, it’ll take more than her ingenuity and Cedar’s combat skills to survive.