Jonathan and Jennifer set sail, incognito, on a gambling ship in an attempt to crack a counterfeiting ring.

The Harts return home and find their house ransacked. During the clean-up, they discover a hidden hallway and vault. The Harts and their friend Ida are sealed in the vault when the crooks return to claim the municipal bonds hidden in the vault.

Intrigue in Vail lead Jonathan and Jennifer into the midst of severe bizarre murder plot, including an electrifying scheme against them.

Jennifer, flying a kite in the park, falls and hits her head. She's hospitalized with a slight concussion. While in hospital, she witnesses the murder of another patient and tries to convince Jonathan of the strange crime is being covered up.

Jennifer's death scene in an amatuer production could become the real thing when the director realizes she can identify him as a murderer of a young playwright.

A deranged woman who works for Hart Industries has an obsession for Jonathan. She sees Jennifer as a threat to her fantasies of love and finds it essential to eliminate her.

Jonathan witnesses a murder. In his rush to approach the scene of the crime, he is hit by someone on a mo-ped. The blow to his head causes temporary amnesia and the killer must get rid of Jonathan before his memory returns.

At the opera, Jonathan is mistaken for a hitman and is given an envelope containing $100,000 for the job. When the messenger is murdered, Jonathan poses as the hitman in an attempt to save the victims life.

The Harts' unscrupulous lawyer hires an assassin to eliminate Jonathan with plans to court and marry Jennifer and thus gain control of the sizeable estate.

The Harts are invited to a unique, off-beat party -- a treasure hunt at a haunted house. When another guest is murdered, the Harts race against time to find the murderer before someone else becomes victim.

Chief accountant of Hart Industries, Stanley Friesen, is set up to take a murder wrap after an evening on the town. In an attempt to clear him, the Harts retrace his steps and discover a gambling ring using the Nightlife as a cover.

The Harts suspect a college fencing champion of being behind a murderous drug ring. Jonathan fights a razor-sharp duel with the sadistic student.

Freeway runs away with a gun used to murder a wealthy neighbor. The Harts get involved in capturing the killer and intercepting a multi-million dollar jewelery shipment.

Jennifer's article on the world of high fashion leads to Jonathan and Jennifer modeling for a famous photograper while trying to determine who is murdering beautiful models.

The Harts become involved in the world of espionage when Jonathan purchases an antique car for Jennifer. A mysterious jet-setting couple will stop at nothing to acquire the classic auto.

An article written by Jennifer leads a prostitute to ask for her help and the Harts go under cover to bait a killer who is murdering prostitutes.

The Hart home is stripped of everything. It looks like an inside job and all clues point to Max's new love. When Max is framed for murder, the Harts intervene.

Jennifer has her protrait done as a gift to Jonathan for their anniversary. When the young artist is murder, the Harts mingle in the high-society art world where Jennifer becomes the target of a shady art speculator.

When a bridegroom disappears abruptly and leaves his wife, who is an acquaintance of Jennifer's, to face a couple of thugs by herself, the Harts step in to help her.

Jennifer is mistaken for her look-alike, Dominique, and is kidnapped by ruthless killers. With the help of an unscrupulous columnist, the police, and the real Dominique, Jonathan devises his plan to save Jennifer.

At a croquet game in Hawaii, a player is stabbed and dies at Jonathan's feet, muttering something about a key. Two of the spectators suddenly become interested in the Harts.

An employee delivers some papers to Jonathan, along with evidence of a murder. She hides the clue in Freeway's toy and the Harts are held hostage by the murderer.

After extending her hospitality to a young author claiming to be a distant cousin, Jennifer experiences a series of near fatal accidents.

When a prominent lawyer is murdered, two close friends of the Harts are accused. Jennifer sets out to clear the wife while Jonathan attempts to absolve the husband.

A Hart Industries chemist is shot and the Harts suspect a female scientist who has discovered a powerful new narcotic. Jennifer and Jonathan find themselves in a weather chamber subjected to brutal and swift changes in temperatures.