It's sometime in the near future. Grey Trace, in liking the tactile satisfaction of working with his hands in being a mechanic, has not embraced the technological revolution, unlike his wife Asha Trace, who works for one of the larger computer companies and who uses an electronically controlled, fully autonomous vehicle to get around. In a violent attack by a group against them, it happening even with technological safeguards to prevent such, Asha is killed and Grey rendered a quadriplegic. After months on the case with those technological advances providing little usable information, Police Detective Cortez has only had a few leads which seemingly have got her and, by association, Grey no closer to catching the perpetrators. Partly in a gesture as a friend, reclusive computer genius Eron Keen, one of Grey's customers, has developed a revolutionary new technology that he is calling Stem which he believes would alleviate Grey's physical disabilities. Not turning Grey into a robot, Stem instead would be a conduit between Grey's brain and his motor functions. Initially reluctant to go through with the procedure (to have Stem implanted) in not having anything to live for, Grey ultimately agrees, with Eron's caveat that Grey cannot tell anyone (Eron needing to keep the technology under wraps for the time being). Grey therefore leads a double life as a fully functioning human and a wheelchair bound quadriplegic. However, Grey discovers that Stem not only will allow him to walk again, but also to act in superhuman way. Stem, that can talk via a sound wave generated voice only to Grey, is an artificial intelligence that can take control of Grey upon Grey's okay. This development leads to a standoff of sorts between three people: Grey, while abhorring violence in its general nature, wants to use Stem to exact revenge against those who killed Asha (the attack against them appeared targeted as opposed to random); Detective Cortez who comes to believe that Grey, despite being confined to a wheelchair, is behind attacks perpetrated against people that were on her suspect list; and Eron who may want to shut down Stem if he discovers that Grey is using Stem for unauthorized purposes, such as vigilante acts by Grey which would indeed contravene their gentlemen's agreement.—Huggo