Eric rightly predicts that the kids will only be more trouble in the new school year, yet Annie enrolls in a college course. Simon's only friend is Jim, who drags him along into minor vandalism as a gang initiation. Matt grudgingly admits that Heather left him at the altar; Lucy learns that Andrew Nayloss made an irreversible mistake in France (his father sent him to Europe to keep him far away from Lucy over the summer). Mary starts a minimum-wage job and gets a credit card and still doesn't see college in her future.

Matt blames his first-ever bad grade, for the crucial course organic chemistry, on everyone and collect excuses to delay studying rather then seek help. Simon is desperately lonely again after Jim's ma absurdly blamed him, but finds unhoped popularity when helping Lucy campaign for ball queen. Eric worries more about a surprise visit then the obvious reason, another attempt to make Mary see sense now she's behind with her car insurance payments.

Matt suddenly gets bombarded with phone calls and pages at the hospital during his orderly duty, which might even get him fired. Simon wants him to drive him on his date with college girl Lulu, who falls for Matt. Eric can't find anyone to join him on a 'guys' pool night, but he ends up having a blast with parish bachelorettes; meanwhile, Annie meets with her child-psychology professor (who doesn't like kids!). Lucy and her charming lab partner "babysit" an egg; Mary reluctantly joins in the Friday 'private hour' of her pizzeria colleagues, teen parents Frankie and Johnny.

Simon has another hot date, college girl Marcia, but when Matt turns up as driver, she only has eyes for the med student, although Simon gets the porch kiss. Lucy dates and agrees to go steady 'light' with Mike Pierce, whom she met in a dean's office, where he offered to help her apply to colleges, but doubts again after learning about his mental history. Their parents found none of the kids still interested in family movie night, nut discover too late sneaking off for 'intimacy' never goes unseen, this time even worse. Mary nearly gets arrested with teenage parents Johnny and Frankie, who are caught smoking marijuana just after her visit.

High school freshman Simon desperately looks for a new image, but clothes nor hairstyle do the trick, so he ends up with an earring. Matt is puzzled when a girl he approaches in the library calls her brother's help against him as 'stalker' after hearing he once dated Heather. Mary breaks every rule and promise when babysitting for Hank by taking in Frances's baby so her 'friend' can spy on Johnny, but the Camden parents' pool night just there makes the real, for all concerned unpleasant difference when Eric blindly assumes Johnny to be an abusive adulterer, while Frankie rather trapped him.

Irresponsible 'adult' Mary fails to realize how deep she's sinking, but both parents and siblings piece together from various sources she's about to hit rock-bottom but have no idea how to help? Eric can barely keep Annie from intervening directly before they know everything. The kids decide to 'borrow' enough from the twins' full piggybanks to cover her debts, but creditors seeing cash convince her to 'refinance, which would mean even more interest.

The monthly day when the twins' piggybacks are enriched with §10 is ahead, so the siblings fear the game is up unless Mary manages to repay the 'loan', but now her debt is reshuffled she idly spends her days in the movie theatre. So the Camden parents soon learn the dreadful truth they already dreaded. After pondering how to help her, a family intervention proving she's still in haughty denial, the last resort is packing her off to Buffalo, to be taken in hand by the Colonel.

Simon lets his mate Luke set them up with the Murphy twins, who fall for his cool 'bad boy' image by association with Mary, but the vixens make the knaves join them in shoplifting and other mischief. Matt falls in love at first sight with a girl in a wedding dress, actually model Julie. Only Mike teaches Lucy how to handle gossip. Annie seeks comfort with a friend, positive thinking guru Robin, who turns out rather negative.

Robbie and Cheryl ask Eric to marry them because of her pregnancy. He smells a rat and learns just in time that she intended to trick Robbie, who is grateful to escape a loveless marriage and offers to stay away from Mary. Lonely Simon has joined punk Norton's schoolmates gang. Lucy, who is lightly butt-slapped, and the Camden parents, make huge scenes over inappropriate remarks from some of the knaves, treating Simon as if he 'hates women'. Matt tries to help both sides understand, but fails, yet a real incident shows Simon's truly good nature. Matt can go for Priscilla after hearing from Heather she's dating another already.

Robbie's ma lost her house and moved away without him and moving in with Cheryl also fell through, so Eric finds him studying outside, yet keeping up top marks. He promises to find a shelter and takes him home meanwhile. Despite embarrassing episodes, all the fault of Camden girls, Robbie proves himself a model house-guest. So Matt finds the couch occupied when chased from his dorm by John, who is completely besotted with Priscilla Carter. Simon keeps is foxy new date Sasha a secret until she arrives in a BMW. Lucy is passively jealous when Mike Pierce announces he got early college acceptance, then goes over to make up and thus discovers his ma's disabling mental condition.

A month later, perfect house guest Robbie is getting popular with most Camdens, except Annie who childishly splits hairs about his domestic input, meant to help her but making her feel redundant, while Ginger takes care of grandpa. Matt is unwilling to stand by John when he meets the Carter parents and seeks refuge with Heather, whose boyfriend Thomas gets them off their backs by suggesting they're a sheets magnate family. Mary starts a round of panicking with a false rumor that Robbie is dating Lucy. Simon is flattered when Robbie asks his financial advice and starts copying him, even Matt follows suits walking around shirtless. Robbie finds a surprising job and the perfect thank you gift.

Eric threatens Robbie with eviction because he thinks he's keeping secrets about Mary. The house is abuzz with secrets and preparations for an elaborate surprise party for Eric's birthday. Johnny drops Mercy on the Camdens' doorstep after Frankie abandons them. Mike trusts Lucy enough to look after his mother for a day, during which the woman surprises her, both by speaking and by what she says.

Robbie is not amused by week-long roommate Matt's jealous whining, but still helps him make up with John, who lacked the courage to tell Priscilla her 'Japanese' room remodeling disgusts both guys. Mike decides after a kiss without chemistry to trade in Lucy for Elaina Casey, while matching Lucy with Mike's friend Jeremy. Simon and Robbie prevent suddenly jealous Lucy's reactions spoiling the whole partner-switch, which thus ends well.

Everyone but Lucy is stuck home celebrating the twins' birthday on Valentine's Day; Lucy and Jeremy keep running into Lucy's ex-boyfriend.

An item found in a lost wallet starts speculations whether it's Simon's or Robbie's and how to make sure it doesn't mean their dates go too far. None of the siblings gives Mary the triumphant welcome she hoped for at her first weekend visit, so Robbie is scolded for not wildly kissing her.

Robbie's father Ed Palmer, a deadbeat who left the boys very young, turns up and slickly gets free board, next convinces his boy to move out and rent a room together. Eric perseveres to make Robbie realize he can't waste his future on a super-dad that never existed, as his very imperfect mother always claimed. Simon's social life clashes badly with parental essay standard demands. Matt is furious to find Ruthie lied to use him in willful disobedience. Lucy hangs out with classmate Ashley's 'cool' mother Serena, only to find a 'regular' mother is better.

Matt is terrified when summoned stat for a psychological session, standard for med students. After an unsatisfactory attempt to be 'coached' by therapy-experienced Mike, Matt lands with Doc, who turns out to be fraud and yet a godsend. Simon wants to break up with older, yet immature Sasha, but lets various advice how to go easy on her complicate things for him. Eric confronts a rather blunt hospital doctor about what to tell terminal patients like Harold Mann about their life expectancy and why.

Robbie is told last, despite Camden's advice for her to be open, that Mary has bumped into her ex Wilson, who does a course in Buffalo, and agreed to a dinner at his place. Robbie is doubly vexed as he immediately calls her after meeting a lookalike, Marie, also a basketball player, whom he asked over to get hold of her study notes. Matt meets and dates Cheryl before he realizes she's Robbie's ex. Mary also bumps into Lucy's Jeremy.

Robbie wonders why Matt is suddenly so friendly, ignoring it's because Matt dates his ex Cheryl, who wants him to tell Robbie but doesn't push that, while Robbie spontaneously tells he studies a course with Heather, who needs his help. Simon feels a social outcast when nicknamed 'virgin Camden' because his mother assured Sasha's blabbermouth ma he's sexually inactive, but actually schoolgirls line up to date him. Viciously jealous, Annie meanly forces Eric to give up counseling Serena, yet denies that's her doing and sticks to her guns after Ruthie commends her as bitchy selfishness-model.

Only Robbie refuses to sign, Eric alone not being eligible, Ruthie's petition against a popular ethics teacher Miller's rumored prejudiced dismissal. Robbie learns about the household rule you can't complain over 18 about anything vaguely political without registering as a voter. Matt is first to work out the televised petition commotion is an unsavory misunderstanding, for which the school kids are tricked into fake detention by her brother. Annie's pa recently found out and now wants her and the family to know she has an older but illegitimate sister, Lilly, from his late first love.

Robbie panics when Mary announces she's returning for the summer months, so he tells her to follow parental instructions not to date her all that time. Mike inspires Lucy how to stay with Jeremy now he's accepted to Juliard: marriage, so they get engaged. Matt is dumped by Cheryl for not telling the family about them, but that gives him the courage and more reward then he bargained for. Wilson was dumped but traveled all the way home, just when Mary's claim of sexual intimacy with Jeremy make Robbie deck Lucy's equally startled fiancé. Simon and Tim discover Deena dated each of them behind the other's back. Serena abuses her lonely birthday to make a move on therapist Eric, while hardware shopkeeper James Carver courts long-oblivious Annie.

Robbie gathers the courage to tell Mary openly, now her lies are exposed, their relationship is over, staying with the family his priority. Simon nurses his broken heart on account of Deenah, refusing to become 'just friends' again. Wilson bonds, while bunking, with Matt and Robby, and demands for Mary to return and go steady in New York, or break up completely. Jeremy forgives Lucy for doubting her fiancé's fidelity. Ultimately Eric helps her transfer to his New York alma mater, near Juliard. The Camden parents finally realize Serena and James are seducing them, ward off each suitor and match the lonely hearts.