A bio-engineered creature called a Syngenor (which stands for SYNthesized GENetic ORganism) takes refuge in Los Angeles's sewer system, going into the streets at night in search of human spinal fluid. The police are stymied due to the lack of eyewitnesses and fingerprints, and consequently are ridiculed by the news media. They only link the cases by the killer's brutal feats of strength, such as ripping the door off a car and pulling on a victim's hair hard enough to break her neck. Ted Londergan, a former detective turned novelist, is repeatedly asked to look at the case by his former partner, Detective Lou Capell, but he refuses. Ted is far more interested in courting Jennifer Stanton, who he met by accidentally backing into her car. Jennifer is initially uninterested in his rude and eccentric personality, but is charmed by his persistence and has sex with him on their first date. When Jennifer is attacked and left in a coma, Ted experiences a change of heart. A young woman named Sherry Carpenter comes forward and tells Ted that Jennifer's spinal fluid may have been drained by a Syngenor, which was created at a laboratory where she worked. Its creator, Dr. Ed Amberdine, worked on the project alone, so after he died no one continued to monitor the Syngenor. His notes indicate the Syngenor would be dangerous if allowed to reach maturity. Sherry says that the Syngenor's attacks usually take on the appearance of a
brain tumor, so the body count has most likely been massively
under-reported. The police chief closes the case, identifying a man killed in a shootout with police as the killer, seemingly in order to end the media embarrassment. Ted and Sherry go to the laboratory to get Amberdine's notes and find a half-dead sewer maintenance worker. Realizing the sewer passages are the Syngenor's means of moving about without being seen, Ted and Sherry descend into the sewers, where they find the Syngenor's lair. Inside are a number of unconscious but still living humans attached to embryonic Syngenors by feeding tubes; the original Syngenor reproduced asexually to create the progeny. Ted shoots the embryos. Drawn by the sound of the gunshots, the adult Syngenor arrives. Ted shoots it but it proves to be bulletproof. He and Sherry flee up to a metal workshop. The shop's exits are all locked, so Ted decides to lure the Syngenor onto a
drop forge instead of fleeing. However, the Syngenor catches him and attempts to drain his spinal fluid. Lou arrives and shoots the Syngenor, knocking it back onto the drop forge. Sherry then activates the machine, crushing the Syngenor. Jennifer awakens from her coma but has gone mad, experiencing hysteria and fearsome hallucinations. ==Cast==