The Neon Rain is a Dave Robicheaux novel by James Lee Burke. In this novel, Dave finds a young girl's body while fishing in Cataouatche Parish. The investigation into this girl's death brings Dave to the attention of some very evil people, including members of the American government, who would rather kill Dave than allow him to stumble onto the real nature of their criminal endeavors. The Neon Rain is a dark and gritty detective novel that takes Dave to the edge of darkness where he nearly loses his soul, then brings him back again.

Dave visits Johnny Massina on death row the day he is scheduled to die. Johnny has asked for Dave, deciding to repay all his kindnesses in the past by telling him a rumor that has been floating around Angola. Johnny tells Dave that some very bad men want Dave dead. Dave tells his partner, Cletus Purcel, about Johnny's story. Cletus takes Dave to meet with Wesley Potts, supposedly the source of the information. Wesley tells Dave that Julio Segura, a Nicaraguan, wants Dave dead because he is investigating the death of a young girl found dead in Cataouatche Parish.

Dave found the dead girl while fishing and requested an autopsy be done after he noticed some irregularities about the girl's body. However, the local sheriff refused to request an autopsy, ruling the death an accidental drowning. Dave tries to persuade the sheriff to change his mind only to be harassed on the side of the road by two deputies. Dave gets the better of the deputies, ties them to their front bumper, and catches a ride back into the city with a young woman who happened to be passing by at the right moment. This girl, Annie Ballard, is kind and attractive, so Dave asks her out. Before going to her home that night, Dave makes a stop at the home of Julio Segura to ask him about the rumors Wesley has been spreading. Segura denies knowing who Dave is and has him and Cletus escorted off his property. That night, however, Dave is attacked when he arrives at Annie's house.

Three men led by a man named Murphy tie Annie up and force Dave's head into a bathtub when he refuses to tell them where a man named Fitzpatrick is. Dave has no idea who Fitzpatrick is. Annie manages to get her feet lose and makes enough noise to attract the neighbors. Murphy and his men leave. The following morning, Fitzpatrick shows up at Dave's houseboat. Fitzpatrick is a federal agent who has been investigating Segura's involvement in weapons trafficking to his home country of Nicaragua. Fitzpatrick makes a great show of expressing regret in involving Dave, but Dave knows that Fitzpatrick wants Dave's help.

Dave wants to find the three men who attacked him at Annie's, so he decides to arrest Segura in order to persuade him to answer a few questions. However, the bust goes badly and Dave ends up killing Segura. A short time later, Dave is kidnapped out of his houseboat. Murphy and his men force Dave to drink alcohol laced with drugs and then put him and Fitzpatrick, whom they have tortured, into Dave's car. The car is put into gear and allowed to fall three stories to the street below. Dave survives, but the car bursts into flames and Fitzpatrick is killed. Dave has a history of alcoholism, so the IAD does not believe his story about his kidnapping. Instead, Dave is placed on suspension until the investigation is completed.

Dave begins drinking again. In his drunken haze, Dave calls the CIA and makes threats against Murphy, who he believes is a CIA agent. Dave later goes to the home of General Abshire, the man he overheard Murphy's men discussing as though he were their boss. Dave is arrested and charged with carrying a concealed weapon. The charge causes Dave to sober up. However, Dave is still determined to clear his name. Jimmy, Dave's brother, arranges for one of the men who kidnapped him to come to his house. Dave gets the man to confess to the kidnapping on tape, but the IAD detective Dave gives the tape to does not like Dave and does not believe the tape is reliable. Dave becomes enraged and punches the man.

Dave goes to Potts and learns where another of Murphy's men lives. However, when Dave arrives the man is already dead. A witness identifies Cletus as the man's killer. Dave sits on this information, unsure what to do about it. Later, a friend of Jimmy's tells Dave where he can find Murphy. Dave goes to Murphy's house and prepares to bring him back to New Orleans. Unfortunately, Murphy pulls a gun on Dave and Dave is forced to shoot him. When Dave goes to his boss to confess this death, however, the man's body has disappeared along with all evidence of the crime.

The federal investigators locate a warehouse filled with guns that Murphy and his friends planned to send to Nicaragua. Dave goes to General Abshire and tells him about this discovery and warns him that the police will come for him eventually. Abshire does not seem concerned, however. Dave learns a few days later that he has been cleared of all charges. However, Dave decides not to return to the New Orleans police department, but to go home to New Iberia with Annie instead.