A crooked police chief enlists Vail's aid to track down an escaped prisoner who had been arrested for loitering. Vail learns from a newspaper reporter that the charge was trumped up and the escapee chances of surviving another arrest are slim.
An escaped, wounded robber holds a young man and wife prisoner in their isolated swamp home, but when he succumbs to the injury, the couple are left with a moral conflict over returning the stolen loot.
Vail comes to a large landowner's home seeking to force him to pay back taxes or move out. Instead he finds the old man's been murdered, so he then tries to investigate the suspicious, but hostile family members.
Teenager Piney Danning shows up telling Vail that her neighbor, who lives in an isolated area, is seriously hurt. But Vail needs assistance reaching the injured person because he's unfamiliar with that section of the Everglades.
A number of Glades County businesses have been victimized by a safecracker and Captain Benson is on the hot seat. The safe company sends a pair of private detectives to assist the local police with their investigation. While the detectives use the latest scientific equipment to arrest a suspect, Linc uses good old-fashioned legwork and a network of informants to track down the real perpetrator.
Lincoln Vail enters the trackless Everglades pursuing a no-account swamp rat robs a general store and fractures the skull of its proprietor. Linc is forced to drag his prisoner back to town through the marshes on foot after the his airboat breaks down. To make matters worse, the crook's brother chases the pair with the intent on rescuing Linc's prisoner.
A trail from a break-in a general store leads Link to an illegal gambling operation where the proprietor is fleecing the county's inhabitants while their children go hungry and without proper clothing.
Coley Jarrett, an up-and-coming boxer, returns to the Everglades after defeating a leading contender. He becomes the target for every would-be tough guy in the 'Glades, as well as mobsters who are angry that he wouldn't take a dive when ordered to do so. When Coley refuses to testify against the racketeers, Linc uses the fighter's girlfriend to change his mind.
Captain Andy Benson gets word that a deported mobster plans to return to Miami via the Everglades and rounds up Linc to help him make the arrest. In the ensuing gun battle, Benson is shot and Linc vows to avenge his boss even though he's been suspended from duty.
A backwoods family hold Linc responsible when one of their kin is bitten by a rattlesnake when the constable was chasing the fugitive. They capture the lawman and drag him into the heart of the Everglades and leave him without food or water to die of exposure..
A bride is horrified when her husband changes their honeymoon plans at the last minute and takes them into the Everglades to camp. The groom's jealously and desire for secrecy makes her worry about his secretive past. Clues lead her to believe he's the infamous "Bluebeard killer" who murders his new brides in out of the way locations.
Following his wife's death, a man abducts his young daughter after being served papers regarding the child's custody. Linc must find the pair immediately because the girl has been bitten by a rabid dog.
When Linc captures a husband and wife whom he suspects of beating and robbing a pretty Seminole girl. When the young woman refuses to identify her assailants, Linc suspects that her fiancé plans to exact his own revenge without involving the authorities.
A pretty schoolteacher meets with resistance when she tries to open a school in the heart of the Everglades. A trio of crooks fear that, by teaching the local inhabitants to read, they'll realize that they're being cheated by the gang.
When Cappy Royal claims he was bitten by a performing chimpanzee, his father gets a court order to kill the animal and Linc is ordered to carry out the execution. Linc believes that the animal has been falsely accused and sets about finding out why the boy lied.
When a Veteran's Administration official travels to the Everglades to meet with Willie Keene about additional benefits, gets driven off by his shotgun wielding relatives, he turns to Linc Vail for assistance. Linc learns that the signatures on recent government checks that had been cashed in Willie's name were inconsistent with earlier ones and decides to investigate.
Will Moody is out of prison after an armed robbery and returns to the area. Odella Burns, who scarred Moody during the crime, is fearful and asks Vail for protection against any revenge from the felon.
Linc's plans for a long weekend in the Bahamas is dashed when his friend, Pete Hammond, a known poacher and scofflaw, is accused of murder. While Linc tries to poke holes in the witnesses' statements, another murder takes place.