The Norths spend the weekend at the country estate of a successful writer Jerry's trying to lure to his firm. The party turns ugly when despised rival publisher Ned Waters shows up. His soused wife quickly downs her husband's drink and promptly falls over dead of poisoning. Any one of the group had motive to want Ned Walters dead.
Hidden inside the library book that Pam checks out is a breakthrough formula placed there for safekeeping by a researcher. It must be a valuable property because someone's willing to kill to get the document. The murdered scientist worked at the Potter Industrial Research Lab where everyone clearly is hiding something.
During a driving rainstorm, the Norths' car gets a flat tire, leaving them stranded in the woods. They spot a seemingly deserted house nearby, when suddenly they hear a woman scream. Running to the house, they find a message scrawled on an upstairs window, leading to a horrible discovery in the basement.
Curious about a beauty contestant who could easily be mistaken for her twin, Pam finds herself backstage at the Miss Venus contest where she fills in for the missing Kitty Pomeroy. Kitty has made numerous enemies of her betrayed lovers and their scorned wives, so its not surprising when she's found dead in the prop room.
Someone's been secretly photographing Madame Suzi's latest dress designs and leaking them to competing, cheaper dress stores. Pam drags Jerry to Suzi's to see a preview of the latest fashions when a model involved in the stealing scheme takes the stage and promptly falls over dead.
Lt. Weigand and the Norths become trapped in the rural home of Dr. Arno, a physician treating a homicidal maniac who's hiding somewhere in the house. The group stages a fake murder scene, hoping the mysterious "Patient X" will be drawn into the open. Instead, when the lights are lowered Dr. Arno's secretary is actually stabbed to death. Once Weigand learns the actual name of the patient, he makes some phone calls and learns they're deal with a real-life Jekyll and Hyde.
When Kovack, an uncouth pulp writer Jerry is publishing, invites them to his country retreat, Jerry and Pam reluctantly undertake the arduous journey, only to find upon arrival that Kovack never invited them.
The Norths and their newly married friend Helen drive out to her recently acquired country home and all is not well. Aunt Clara is missing, a stranger has taken up residence in the house, a dead man falls out of the grandfather clock, and a frightening old man with a rifle prevents them from leaving.
An accountant with only a few months left to live devices a scheme to fund some luxury for his final days. But his scheme and new lifestyle sets into motion a chain of events that draws a number of other people into this murky affair.
A toddler is lost and found numerous times after being left at the North's door. The mother dropped off the child after leaving her race-obsessed bookie husband. An incompetent detective hired by the father repeatedly grabs and loses the tot. Drunks from a bar, seeing a quick buck, join in the kidnapping fun. All the while, a crabby female cop tries to unravel the story.
The secrets of the Honey Moon Inn come to the surface during the North's fifth anniversary visit to the hideaway. Inn owner Margaret is surprised by a marriage proposal from a fresh-from-prison ex-beau, the murdered sheriff is found in bigamist Chef Francois' pantry, and at least one of the household members has a secret marriage.
The warden at the State Penitentiary asks the Norths if they wish to interview a high-profile inmate for a potential book. While they're in the prison, a disturbance breaks out that suddenly escalates into a hostage situation--with the Norths as the hostages.
Pam is disappointed when the fur she thought was her birthday present is retrieved by a store representative; the man says it was delivered to her by mistake. It turns out that a con man, posing as Jerry, charged the fur to the Norths' account and then made off with the mink.
Pam becomes involved in another murder after the phone company switches the Norths' number with that of a crooked bookie. She takes non-stop phone calls from gamblers placing bets on horses, but has no idea what's they're all talking about. She's on the phone with the shady bookie when he's gunned down in Grand Central Station.
Chuck Walker, a North family friend, is discharged from the Navy for being underage. Planning to rejoin on the West Coast under another name, he needs some money for the trip. After being involved in a bar fight with a drunk who's robbed and dies, Chuck is charged with murder.
The manicurist at Jerry's favorite barber shop recognizes a customer as a wanted murderer, but instead of phoning the police, she devises a plan to blackmail him. However, her scheme goes awry, with deadly results.
The Norths go to a training camp so Jerry can interview the up-and-coming prizefighter, Vince McKay, for a future book project. Unfortunately, the boxer collapses in the ring and dies. It turns out that McKay was hard to get along with and made promises to women that he didn't intend to keep. Many people had it in for McKay, but which one fed him the rat poison?
Pam and Jerry run into an old war buddy who is visiting his mother on the midway of a traveling carnival. Problems surface when the crooked stepfather (Joe Vitale) is involved in a plot to rig the games. When the Norths begin to unravel a mystery, things turn ugly on the midway.
Jerry is excited about publishing the personal papers a Revolutionary War figure. He and Pam accompany Nathaniel Sykes III to the small town where his ancestor is buried to retrieve the historic documents from his ancestor's coffin. In the next grave over is buried a drifter and a million dollars. A gang of criminals stashed their stolen loot in the grave for safe keeping until the cops lost interest. When the headstones get switched, everyone's in a panic.