Innocent people undergoing elective orthopedic surgery at a university hospital in San Francisco are suffering infections at an alarming rate. Dr. Keith Grant is the chief resident in orthopedics at the hospital. Keith lives in a low-rent apartment with a parakeet named Baby, rides a motorcycle, and is totally in love with a tiny Filipino pediatric nurse named Mary. He was called to treat one of the infections and another case with an even more serious complication. The experiences of these human tragedies profoundly affect Keith. When Keith is asked to investigate the complications, he and Mary become a team of detectives. They share the mystery with Keith's best friend, Matt, a pathology resident and his partner, Duane, who is a San Francisco homicide detective. When the data prove to be too baffling, Keith and Mary call in Dr. Raymond Stuart. Dr. Stuart is a senior member of the faculty, a pediatric orthopedic surgeon who Mary knows and respects for his diagnostic skills. Dr. Stuart lost an eye in a horrible automobile accident and no longer performs surgery. Dr. Stuart agrees to help work on the problems of the complications and becomes the leader of the investigating team. Complications continue and patients die. Other people associated with the hospital are killed in seemingly unrelated incidents. Duane, the SFPD detective, friend of Keith's and partner to Matt, is assigned to the cases which occur outside the hospital. An irascible, foul-mouthed lawyer who is a member of the hospital board undergoes knee replacement surgery at which Keith is the assistant. After surgery, the lawyer barely survives a horrible complication because of Keith's timely intervention. Mary and Dr. Stuart struggle together to treat mysterious illnesses. Dr. Stuart discovers a common factor which links many of the complications and deaths. Stuart deduces that foul play is at work, and that the killer is someone in the hospital. However, the motive and identity of the perpetrator remain elusive. Bits of evidence from the murders outside the hospital and the complications within fall together as Stuart's team investigates. Even the irascible lawyer lends a hand to unravel the mystery.