When Tommy catches a bug, the crew gets its first taste of human illness.

When Dick's evasive about his past, Dr. Albright suspects he's a '60s radical fugitive. Harry joins a CD-of-the-month club, and is swamped with CDs.

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's romance with Mary is out in the open---and she doesn't like it. Meanwhile, Sally wants to be a cop.

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.

While Dick cracks North Rutherford society (to Albright's chagrin), Tommy hangs out with school toughs. Meanwhile, "Mustang Sally" develops an interest in wrestling.

Dick compensates for the loss of Mary's affections with a gain in another area: he puts on weight. Meanwhile, Tommy thinks August is cheating on him.

The Solomons reflect on their sinful ways in an episode that illustrates their misdeeds in clips from past episodes.

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

Dick is all ready to dump Jennifer and try to win back Mary's heart, but then discovers that his relationship with Jennifer has made her jealous. Wanting the old Mary back, who had time for him over her job, he attempts to capitalize on her jealousy by making his romantic interludes with Jennifer very obvious. Officer Don introduces Sally to bowling, but becomes exasperated when she refuses to play by the rules, and so invites Harry and Tommy behind her back.

When Harry's boss Doug starts deducting income tax from Harry's paycheck, the Solomons realize that they have never filed a tax return and that they owe $9500 to the government. To combat this, they invent the 'brilliant' notion of lying on their tax return and Dick reworks the sums so that the government owes them several hundred thousand dollars. Sally attempts to help by setting up a failed home hairdressing business, but when women start arriving for haircuts, Harry and Tommy 'camp up' and take to the 'salon' to help. Lying doesn't work, however, and the Solomons are faced with an audit - and the threat of being exposed as aliens.

Dick is suffering the humiliation of having been demoted from High Commander to Harry's assistant, performing the most menial jobs, while Sally has been promoted to his old role. Tommy is preparing for his high school prom with Alissa, but when the Big Giant Head insists on coming, things start to slide, especially when Vicki, who missed out on her own high school prom, turns up. After ruining the prom for Tommy and Alissa, the Big Giant Head whisks Vicki off to his bachelor pod in space.