Solomon discovers that human bodies can produce feelings, and he's feeling attracted to a college professor with whom he shares an office.

Tommy's ""make-out session"" has an unintended consequence: he catches a bug and the crew gets its first taste of human illness. Martha Stewart has a cameo curing Harry with her apple cobbler.

Dick confronts the harsh realities of middle age when he's introduced to the earthly concept of birthdays - and it dawns on him that he's getting old.

Sally's exploration of the life style of a young adult woman proceeds: Dick assigns her to go out on a date and, not surprisingly, the guy turns out to be a jerk.

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

Dick discovers the emotion of jealousy when Dr. Albright's old boyfriend returns to visit on a promotional tour of the novel he dedicated to her; Harry adopts a stray dog.

Dick's one lonely guy when Dr. Albright goes on vacation; Sally and Harry are lured by skin-care products that promise eternal youth.

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. Meanwhile, Tommy neglects his female pal August to hit it off with an ""easy"" cheerleader.

Dick receives a roundabout lesson in family values from Dr. Albright's loopy brother, who claims to have been abducted by aliens.

Dick discovers the consequences of unvarnished truth when he repeats some of Dr. Albright's unflattering comments at an academic committee meeting.

While Dick and Harry take up painting (Harry takes to it; Dick doesn'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.

Harry joins a CD club and finds the responsibilities of membership overwhelming. When Nina tells Dick that Stanford has no graduate records on him and Dick reacts defensively, Dr. Albright observes that it's virtually impossible to get a straight answer from Dick about his past. As Dr. Albright reminisces about her wild, rebellious times at Berkeley and Mrs. Dubcek contributes some colorful recollections, Dick chides Tommy that, as information officer, he failed to brief the crew on the crucial sixties decade. Dr. Albright becomes convinced that Dick is actually Manny Rosenberg, a sixties activist whom she knew briefly and who has been in hiding from the FBI for decades. Dick denies this but soon realizes that his presumed identity has somehow made him more attractive to Dr. Albright. Later, at Dr. Albright's apartment, Dick thinks that they'll at last be having sex, but Dr. Albright angrily reveals that she and Manny had an upsetting encounter that she still hasn't gotten over, and

Dick dons a dress to infiltrate Dr. Albright's women-only study group; Sally and Harry get jobs at a pancake restaurant.

The Solomons discover that everyone on Earth has roots but them. During a chat with Tommy's teacher Mr. Randell, Dick learns that the teenage isn't ""fitting in"" at school. ""Of course I'm not fitting in,"" snaps Tommy, ""to fit in, you have to be something."" The question is, what to be? Dick grabs an anthropology book for the answer. ""It's loaded with every possible genre of human,"" he marvels. ""It's like a catalogue. We can take our pick."" Dick picks the Italians because, according to a swooning Dr. Albright, they're the sexist people on the planet. Meanwhile, Sally's swooning, too -- for Mr. Randell.

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's""odd"" is because he lacks a father, and sets out nurture the suddenly rebellious Harry -- who then learns that he has a""thing"" in his head, a communications device the others knew about all along. Meanwhile, sparks fly when Sally meets the hostile mother of her boyfriend.

The ever-present influence of television turns the Solomons' first trip to a hospital into a madcap exercise in fantasy versus reality. After Mrs. Dubcek cuts her finger, and the sight of blood leave Sally unconscious, Harry and Tommy rush them to the hospital, where the smell of sterile corridors and the gleam of surgical scrubs remind the aliens of the exciting work of their favorite TV doctors -- work that they practice on several unsuspecting patients. Meanwhile, Dick has work issues of his own when Dr. Albright finally gets her long-coveted private office.

Dick cuts up at a Japanese restaurant, but the big news is that he's there with Dr. Albright, who has finally agreed to date him. But just as they finally consummate their attraction, Harry receives bad news from the home planet: Dick has been replaced by a less benign duplicate, who traps him in the basement and takes charge of Dr. Albright.