The Millennium Group investigates the suicides of identical twin girls born seven years apart. They soon find out that a man and his bizarre family of cloned daughters are preparing for the apocalyptic disaster of May 5th, 2000, when a celestial alignment of the planets take place.

A starry-eyed Sabrina hates to leave Harvey for a family skiing trip to Mars, but Doug, the good-looking and magically talented ski coach she meets there, soon has her forgetting to phone home while they spend a romantic evening together. Meanwhile, Hilda meets a man who claims to be a secret agent on a dangerous mission, which she assumes is just another holiday-on-Mars fib; and Salem takes the opportunity to host a riotous cat party at home.

The Simpson family is watching a Krusty special when Lisa notices that Marge's hair is falling out. The reason, says Dr. Hibbert, is stress. Homer vows to do whatever it takes to get her back to normal. Marge wants him to hire a nanny. They interview nannies, but Homer keeps accusing each applicant of being a man. No one seems to be qualified until Shary Bobbins arrives. She has an instant rapport with the children. They sing songs as they do chores. Everyone else in Springfield loves her, too. Shary is about to leave, but realizes that the Simpson family still needs her. She stays and they become more and more dependent upon her. Eventually her songs stop working, Bart whips cupcakes at the wall and Lisa sits around watching TV. When they tell her that they are happy just the way they are, Shary Bobbins leaves (only to be sucked into a jet engine).

Harm and Mac head to Belfast in Northern Ireland to negociate the release of Lt. Nevin's baby who was, according to Nevin, kidnapped by the baby's father who happens to be a known terrorist. When Harm meets the father, he learns that he isn't the kidnapper, but instead is someone else more deeply involved.

Beavis and Butt-head find a baby bird that has fallen out of its nest. At first they plan to eat it, but Stuart's dad convinces them to take care of it and drives them to the vet.

Mr. Buzzcut brings a speaker from AA into class to teach the students about the dangers of alcohol. Beavis and Butt-head think that if they go to AA too, they could possibly score some beer.

Fabian Cortez helps Apocalypse escape from the astral plane.

A mugging brings a shy woman and the man she admires together and one of Richard's old flames turns up. It's a sad night in A & E, as Matt has had enough of attending the sick and needy from behind the reception desk and is off to serve the hot and thirsty in his brother's bar in sunny Crete. His leaving party goes awry but can he really leave Jude behind?