Before the Trackers, survival was easy.

Two generations ago, Earth's wealthiest citizens — the Hoarders — seized control of the planet's resources, retreated into their heavily guarded Enclaves, and left the rest of the population to fend for itself.

Now, the Hoarders have begun randomly Implanting people with a new kind of microtechnology, capable of converting their unsuspecting hosts into violent and deadly automatons. They also created Trackers, a stealth unit of mechanically and chemically enhanced creatures, fanatically devoted to hunting down and killing anyone unlucky enough to have an Implant.

Amos Morgan and Aubrey Carter, together with a small band of fellow Runners, must unravel the mystery, racing against time before the Trackers locate them.

And before their own Implants change them into ...

Something else.