Jim is sought out by a detective, hired by his wealthy father to locate him and give him plane tickets to come visit him in Boston. Jim explains to the gang that he has been estranged from his family after dropping out of Harvard in the 1960's and changed his name from Caldwell to Ignatowski. Jim agrees to go to visit his father and brings Alex with him, who is curious about what Jim's family must be like. At his father's mansion, Jim's oddness upsets his father and they get into an argument during dinner. Jim is asked to leave, but Alex speaks to Jim's father privately to try to smooth things over. It turns out Jim's father still thinks of Jim as his favorite child, but it hurts him to see him wasting his life when he had so much potential. Jim comes in and convinces his father that he's got a happy life and doesn't need his father's money and they share a moment before Jim leaves.
Industrial espionage is a problem at Hartoy company. When the investigator Jonathan has hired is murdered, the Harts go undercover in an attempt to foil the crooks and save the company from financial destruction.
On Christmas Eve, a terrible blizzard traps Howard and Joanie at the hardware store and Fonzie, Potsie, Chachi, Jenny, and Roger at Arnold's.
Franz goes to Reinhold and tells him he wants to get involved with Pums again. Reinhold still has his suspicions but Franz is allowed to assist the gang with a job. Mieze is upset that Franz is earning money because she thinks Franz wants to be independent of her, but Franz reassures her. Franz brags to Reinhold about Mieze’s devotion and decides to show him what a fine woman she is. In the apartment, Franz has Reinhold hide in the bed when Mieze arrives. She reveals she is in love with another man. Franz is angered and beats her cruelly, but Reinhold saves her and throws Franz out. Mieze goes out to Franz and the two reconcile, though she has been bloodied by him. Franz and Mieze take a trip outside Berlin, where he explains to her he simply wanted Reinhold to see a true woman.
Hawkeye, B.J., and Margaret try to save the life of a critically injured solider so that his family won't think of Christmas as the day that their father died. Meanwhile, Winchester fulfills a family Christmas tradition but has trouble maintaining the anonymity required to keep it a truly charitable act. Even Klinger lends a hand.
Rizzo and the other rats bother Kermit for a spot on the show, so Kermit asks Beauregard to "take care of them." Of course, Bo takes that literally, and treats them as guests. The rats make Beau their president, and manipulate him into giving them food. The rats eventually become so bold that they decide to take over the show. Kermit says Beau has to kick them out, or he goes with them. Beau chooses to stick with his new rat friends, until Miss Piggy enlightens him.
When Roland leaves his cruel, millionairess wife Vivien for a fresh start with his mistress Anna, the snubbed spouse plans to make his life a living hell.
Astronomer Carl Sagan leads us on an engaging guided tour of the various elements and cosmological theories of the universe.
In Hawaii, the Angels get word that an assassin has been hired to kill an envoy from a peace-keeping organization who is scheduled to speak at the convention center in 48 hours.
When a ruthless biker gang kidnaps Officer Clark, the boys gun it to save her, while Sgt. Getraer's wife suffers false labor pains.
The Doctor joins the villagers' revolt against their vampire rulers, unsure how to kill the king vampire. Meanwhile Adric is first in line to join the new vampire order while Romana is laid out as a sacrificial Time Lord for the awakening king vampire and his swarm of bats.
On a Scotland trip, Scooby encounters a Black Knight.
Scooby has to compete with a strong man at a carnival thanks to Scrappy.
Scooby, Shaggy and Scrappy are a Swamp Witch's dinner guests....and they're the dinner! One of the few episodes where the Mystery Machine doesn't make an appearance.
The evil wizard Crom threatens a tribe of humans at the Alamo. They can protect themselves by using a sophisticated Guardian machine that utilizes flying robot drones that can disable the wizard's laser tanks. However, it blows a circuit and cannot be replaced as circuits are no longer produced. Their only hope is to infiltrate Crom's lair in order to use his moon dial, which sends them to Old Earth. In the 20th century, Thundarr, Ookla and Ariel are aided by a little girl named Samantha, who helps them obtain a fresh circuit. The trio return to New Earth and prepare for battle with Crom, but are glad they had a chance to see the preapocalyptic world.
The captain's ex-girlfriend comes aboard the ship and constantly makes passes at him because she feels neglected by her husband. A model pretends to be married to keep away annoying suitors. A man is convinced that a fellow passenger is an alien who turns into a plant every night.
Gretchen attends night classes in order to win her American citizenship. With a lot of hard work and achievement she fails the test. It seems that she remembers more when she's angry, so Benson and Marcy come with her. Benson then uses the anger strategy when she is failing. She gets angry and spews out answers that eventually win her her citizenship.
After meeting a woman through a computer dating service, Rosco plans to get married. Boss plans for him to invite everyone in town to his wedding--except the Dukes. This makes them the only possible suspects for the bank robbery he's arranging to take place during the ceremony. But Boss is unaware that Rosco's supposed fiancé and her gang are planning a robbery of their own.