Jonathan thunders into the glamour and excitement of polo, unaware that he and Jennifer have become targets for murder in a smuggling scheme using a prized polo mallet to transport a $1-million gem.

Jennifer fears for Jonathan's life when ruthless jewel thieves take him hostage during a robbery while he's on a business trip in Paris.

Jennifer races to save Jonathan, who is serving as radar operator aboard a fighter jet rigged by a saboteur to explode during its top secret test mission.

A traditional fox hunt is marred by murder during the Harts visit to England -- and sends them off on the trail of a killer.

Jonathan teams with tennis great Martina Navratilove in a game of doubles aimed at exposing a deceitful tennis pro and the stockbroker who is blackmailing him.

While in Greece, Jonathan and Jennifer race to save their lives and the future of Hart Industries when a European business magnate seeks to destroy them during a cross-country car rally.

A woman claims to be Jennifer's half-sister and her father believes she could be the daughter of his nurse during the war. Jonathan, however, is suspicious and sets out to find the truth.

Jonathan and Jennifer's delightful excursion to the Scottish Highland games is laced with danger when Jennifer becomes the target of a man who is her rival for leadership of a world-famous clan.

The Harts lives are at stake when a valuable ancient jade carving leads them into the heart of mysterious Macao, where they encounter a Chinese arms dealer who has become a threat to U.S. national security.

In keeping with the season's spirit, Jonathan and Jennifer take in a girl who learns that her parents died in a car crash that left her comatose for 7 years.

Jennifer takes refuge in a convent after witnessing a gangland slaying. Jonathan must race to save her when the killer discovers her hiding place.

Jennifer is stalked by a psychotic stage manager who lurks in the wings as the Harts don top hats and tails to perform in a charity benefit in the Big Apple.

Jennifer and Jonathan help Max seach for his lady love, who has fallen victim to a pair of money-hungry crooks.

Jennifer and Jennifer are stalked by dangerous industrial spies after they are entrusted with a dog that happens to be carrying a valuable biogenetic formula.

A young figure skater's dreams of Olympic gold will be shattered unless Hart Industries can mix modern technology with the astounding talent of skater Tai Babilonia.

While vacationing on the exotic island of Rhodes, Jennifer and Jonathan become ensnared in a scheme for the smuggling of ancient Greek artifacts and are nearly entombed in the process.

Jennifer takes on a glamorous modeling assignment, not knowing that the camera is rigged with an explosive device, as Jonathan races to stop the deadly scheme concocted by a vengeful man from her past.

Jonathan and Jennifer pose as a professor and a student in a dangerous scheme to expose the person responsible for the drug framing of Max's nephew, a college basketball star.

The Harts and Max are held at gunpoint when a murderer realizes that Jonathan has incriminating evidence linking him to the death of a champion skier.

The Harts and Max fear for their lives when the debt-ridden brother of Max's penpal believes Max is rich and comes to steal some of his fortune.

Max is taken hostage. The Harts scramble to save him by participating in a scheme aimed at robbing an international jewel salesman of $20 million in gems.