The leader of an alien recon party on Earth discovers he has "feelings" for a professor.

Dick is introduced to the concept of birthdays--and it dawns on him that he's getting old.

While Sally does a slow burn at being the often-overruled second in command, Dick lights up his life by taking up smoking.

When an obnoxious professor dies during a party in his honor, Dick finds the will specifies that he must deliver a “forthright and honest” eulogy about the universally despised academic. Tommy neglects his female pal August to hit it off with an “easy” cheerleader.

Dick discovers the consequences of unvarnished truth when he repeats some of Dr. Albright's unflattering comments at an academic committee meeting. Sally and Harry apply for driver's licenses.

While Dick and Harry take up painting (Harry's good; Dick isn't), Sally takes over the school bake sale with the gusto of Gen. Patton.

A snowstorm -- the Solomons' first -- spoils Dr. Albright's trip to Chicago, leaving her stranded in a truck stop with Dick.

The Solomons learn about the give and take necessary to human friendships when they turn their anthropological gaze to the next-door neighbors.

Dick decides that the Solomons don't ôfit in” on Earth, so he shops for an ethnic group to join. Meanwhile, Sally wants to fit in with Tommy's handsome teacher.

The Solomons' faith in human nature is shaken when they fall victim to crime (""This planet is in a bad neighborhood,"" sighs Sally). Meanwhile, Dick makes Tommy join the school basketball team.

Dick decides the reason Harry is “odd” is because he lacks a father, and sets out nurture the suddenly rebellious Harry. Meanwhile, sparks fly when Sally meets the hostile mother of her boyfriend.

Dr. Albright finally agrees to date Dick and Harry receives an ominous message from the home planet.

While Dick is trapped in the basement, Evil Dick begins a plan to impregnate all women in Ohio.

When Harry runs for city councilman, Dick discovers the complexity of the democratic system and struggles to make the right vote.

Homecoming's upcoming, but Dick can't seem to understand football's appeal. Tommy has a crush on his Glee Club teacher. Sally makes Nina her best friend. Harry gets a job as a security officer.

Harry and Sally discover the true meaning of Christmas at the mall, where they get jobs. But Dick turns curmudgeonly. Tommy tries to find the perfect present for August.

A Frenchman asks an unwitting Sally to marry him so that he can remain in the country. Tommy discovers he has a talent for flower arranging and styling. Dick is inspired to discuss marriage with Albright.

Dick fears his relationship with Mary has grown stale. Tommy's growing tired of August's “perfection.” Harry and Sally switch jobs.

Dick's guilt over hitting a chipmunk with his car spurs him to animal-rights activism. Tommy's in trouble with August again. Meanwhile, Harry joins the Boy Scouts.

Dick, fearing that Mary has him wrapped around her little finger, takes lessons in being "manly"---from Harry. Sally and Tommy have a showdown with the game Monopoly.

Dick's rudeness lands him in a sensitivity-training session. Dubcek's daughter takes Harry to her high-school reunion. Officer Don teaches Tommy how to drive.

The Solomons discover dreaming---and are shaken so much that they might have to go home for repairs.

Shaken by dreams, the Solomons may have to return home for repairs. But Dick doesn't want to go---he wants to marry Mary.

Sally, Tommy and Harry return from the home planet with a surprise for Dick: a bride-to-be.

Dick tries to hide his Janet predicament from Mary; Officer Don suspects that aliens have landed.

Dick quakes at the prospect of a physical exam. Meanwhile, Sally and Tommy house-sit Albright's house on Halloween. Which is bad news for neighborhood trick-or-treaters.

Dick hurts himself playing in a wheelchair, which puts him in one for real; Dubcek's daughter Vicki opts for celibacy, much to Harry's chagrin.

Venusians disguised as gorgeous women plot to plunder Earth of its riches.

While Dick is using the Solomons' car for "casual" sex, Sally decides that she must have a car of her own.

Dick demands that Sally and Harry go to work, so she signs on as Albright's assistant and he gets a job tending bar. Then Dick decides on a career change: he wants to be cop.

Albright derides the Solomons as "weird," so Dick decides to make them "average."

Conclusion. Dick has a rival for the title of Pendelton's nuttiest professor with the arrival of the mysterious Dr. Liam Neesam. Meanwhile, Sally thinks she's losing her touch with men.

Dick tapes a promotional video for Pendelton; Don gives Sally a key to his apartment; and Nina and Harry find each other.

When Playpen magazine arrives at Pendleton, looking for students to pose nude, Sally decides to take part. While Dick encourages this, Don is furious. Dick is horrified when he discovers that Mary posed nude for an art shoot twenty years ago, and tracks down the photographer. Harry decides to test if clothes are "all a big scam" by becoming a nudist. Tommy has his eyes on his new lab partner, Alissa Strudwick.

After three years, the Big Giant Head has finally accepted Sally's request to have her body changed for a man's. For their convenience, the bodies of Dick and Sally are switched. Now, in each other's bodies, Dick and Sally must try and maintain each other's romantic relationships and get accustomed to the changes that their new gender brings, while waiting for their request to be switched back to be accepted. Meanwhile, Harry is left in charge of Happy Doug's when Doug goes on vacation, but becomes worried when a group of burly, tough-looking bikers arrive.

Dick is up for a prestigious grant but his chances look somewhat marred when he and Mary receive chain letters, and Mary, upon throwing hers away, becomes victim to a series of misfortunes. Dick looks toward superstitious rituals and lucky charms for help. Don treats Tommy and Alissa to a series of ice hockey games for which he bought tickets for when he was dating Sally, but Tommy begins to worry that he isn't manly enough to compete with the likes of the players. Sally and Harry visit a hardware store, where Sally takes a liking to a series of workers, while Harry is mistaken for an employee, due to his bright orange shirt.

Dick realizes that he doesn't know how to use a computer and strives to learn how to use one. When he does it takes over his life and he becomes a recluse. Sally and Tommy decide to do away with their old TV in favor of a newer, better one, but end up becoming addicted, wanting all the latest features. Harry and Vicki, however, are trying to get pregnant, but the medical-science part of it is turning Harry off.

It is the day before Dick's birthday and he has ordered Sally, Harry and Tommy to throw him a surprise party. When in class he meets a woman called Charlotte Everly who appears to be very taken by his 'brilliance'. Charlotte first claims to be auditing his class, then later claims to be a reporter, then an intellectual groupie. She and her son wangle her way into his birthday plans, cancel his party and lock the guests that do arrive in the basement. She then reveals to Dick that she knows that Dick is an alien - and she wants to cut him open. Kathy Bates' appearance in this episode spoofed her role in the film Misery, when Dick refers to her as his "number one fan".

When Mary and Nina talk about how good looking Harrison Ford is, Dick decides that he himself is hideous and visits a plastic surgeon to discuss having his face surgically altered. However, when the surgeon tells Sally that she might benefit from having some plastic surgery herself, she becomes paranoid and believes herself not to be good enough for Don. Harry, meanwhile, is chuffed when the surgeon tells him that his face is perfect.

Dick is confused when Nina won't let him accompany her to her Black Student Union meeting, believing it to be a Weight Watchers type club; so, in an attempt to understand the concept, he mistakenly takes the Solomons to a racist white power rally. Dick realizes that the rally was a bad idea, and tries to make it up to Nina by firing her, to release her from what he calls her 'servile role' (as he and Mary's assistant), but she informs him that she is happy in her job. Meanwhile, Sally, Harry and Tommy are preparing to take part in a poetry competition and decide to use racism as their subject.

Dick begins to have erotic fantasies about Nina, and makes the mistake of telling Mary about it, leading to an argument between the three of them. Dick is confused, and Don explains to him that his confession makes Mary feel as if she no longer excites him. Meanwhile, Sally falls under the spell of Margaret Williams, a lifestyle guru very similar to Martha Stewart, and an impressed Mary asks her to cater for a fund raiser she is holding. However, Sally becomes annoyed when the guests do not appreciate all the hard work she has put in.

Dick tries to experience youth for the first time by partying with his students during spring break, but his drunken antics are wasted on Mary, who is trying to relive a favorite, and more relaxing, family outing. Meanwhile, Don and the police have moved into the Solomons' apartment in order to survey a video pirate living opposite. Sally is hugely turned on when she sees Don ordering his fellows about, but he is emasculated when tough government agent Jack McMannus arrives and takes over the operation, and Sally becomes attracted to him.

Pendelton University has a new chancellor, who causes anger when he cuts funding and takes away tenure, so Dick holds a meeting, in which he convinces the faculty to resign en masse. Unfortunately, the chancellor accepts the resignations and leaves everybody in the faculty, bar Dick - who withdrew his own, without a job. Upon finding out about his betrayal, the faculty protest outside Dick's classroom and Mary refuses to be seen with him. Meanwhile, Tommy begins working at a pretzel store with his girlfriend Alissa, but begins to dislike working with her and gives Sally and Harry free pretzels, with which they start their own business right in front of the store.

The Solomons visit a parallel universe, in which they are living in New York City, where Dick is a highly regarded attorney, Sally writes a sex column and Harry is President of NBC, while Tommy is a star on Saturday Night Live. Despite this, Dick is unhappy because he cannot find Mary; however, upon entering a basement bar he discovers her, a failed actress-turned torch singer who has renamed herself Kiki Lyle. Meanwhile, Sally discovers that Don is the Mayor of New York, and that she isn't his girlfriend, but his mistress.

Dick takes Mary up to his penthouse and wines and dines her, but she tells him that she doesn't believe in true love anymore, no matter how hard he might try to persuade her otherwise. Meanwhile, Sally isn't happy being second fiddle to Don's wife so she asks him to break up with her. Don, however, wants to run for president and so refuses, so Sally breaks up with him; while at NBC, Tommy's huge ego and demand for a high pay on Saturday Night Live leads Harry to fire him.

Tommy is looking for a college to attend and Dick steers him away from the big names such as Harvard and tries to convince him to attend Pendelton instead. Upon taking one of Dick's classes, however, Tommy decides that Dick is a lousy teacher and that he would rather look elsewhere. Outraged, Dick orders Tommy to go to Pendelton. Meanwhile, Sally is concerned that Don isn't listed one of Rutherford's ten most powerful men and so she gets him a job working for one of them.

After hearing the crowd sing The Star Spangled Banner at a baseball game, Dick realizes that humans are passionate about their country of origin and attempts to become more American, only to discover that he actually has a Canadian passport. Meanwhile, the other Solomons' work on the basis that all Americans are equal, and start an equality system in the house, putting Harry in charge, who makes everybody wear the same uniform and rations household items, until Tommy begins to fear that they are losing their individuality.

The Solomons are struggling to take in the news - they have been ordered back home due to Dick's transgression with Liam. Dick's first instinct is to ask Mary to come, so he takes her to the planetarium before breaking the news to her that they are leaving, and asking her if she will join them. Meanwhile, since admitting his fear to Sally, Don has decided to quit the police force and open a muffin store, but Sally is disgusted by this career choice and decides to whip Don into shape - and turn him into a hardy police officer. At home, Harry and Tommy are attempting to organize a farewell party for the aliens, but have no money, so they decide to max out their credit cards and not worry about paying the bill, since they'll be halfway across the galaxy - they even hire Elvis Costello to sing Fly Me to the Moon.