Zack Vella is a technology-obsessed bioengineer working for Titan, a robotics and AI facility in the vertical metropolis of Brulle. Zack is also a 'borg', one of the first people to undergo Titan's cyborging procedures. Having both his good legs voluntarily replaced with advanced prosthetics, he becomes heavily reliant on Titan's bio-blood.

Eager to break free of his dependency, Zack sets up a rudimentary lab, but becomes careless and lets his bio-blood run low. When the city's infrastructure is attacked, the panicking citizens blame Titan and it’s borgs, leaving Zack blocked off from access to more bio-blood.

Racing to escape becoming a sitting-duck for the violent borg-haters, he is forced to venture into the dangerous denizen of Alta to seek out the information he needs to fix his malfunctioning lab. Accompanied by an unexpected companion, Zack wanders into the heart of all that it means to be—and to not be—human.