A sweep who works in the Colorado compound, Lawrence Grey releases the viral Zero.
Like all sweeps at the Chalet, Grey is a convicted pedophile. He gives himself regular Depo-Provera injections and takes other hormonal and steroidal medications to suppress his sexual compulsions, all as part of his probation condition. As a side effect, he and all the other sweeps are suggestible and docile.
Grey is often assigned to monitor Zero, the viral who was once Tim Fanning. Zero uses his telepathic abilities to communicate with Grey. Eventually, he is able to convince the sweep to release him, while other sweeps release the Twelve. Once he is free, Zero draws Grey in close enough to attack him, biting him on the shoulder. Brad Wolgast, Jonas Lear, and Amy encounter him during their escape from the facility. He is stumbling through the hallways, blood pouring from of the wound, dying.
Grey wakes up in a motel room several weeks after the escape of the virals. Another sweep named Ignacio has been watching over him during his recovery. Ignacio gives Grey a gun and encourages him to kill himself while he still can. He claims he waited too long, then leaves to join the viral Martinez—also known as Ten—leaving Grey alone and confused. He is strangely rejuvenated and discovers he looks much younger and healthier. He takes the gun, but does not kill himself.
During his flight, Grey meets a highly distraught pregnant doctor named Lila Kyle, the ex-wife of Brad Wolgast. They travel together until they are captured by Horace Guilder. Guilder and his staff feed off Grey's blood for almost 100 years in order to remain young and healthy.
Grey is killed when Lila finds him and commits suicide by blowing them both up.
- The Twelve, Chapter 5.
- The Twelve, Chapter 25.
- The Passage, Chapter sixty-six.