Playing in the park with cute little Billie, handsome student Wilson West meets Mary and both get butterflies. Wilson's impeccable charm, doctor-pa and record pass even Eric's paranoid muster, but on Sunday he divulges that Billie is not kid brother but his own son. At the airport to pick up maternal grandpa Charles Jackson, Matt is smitten at first sight on a girl he later traces and learns is deaf Heather Cain. They date, but she flees the party after some youths make fun of her sign-language. Eric and the kids welcome grandpa's new 'significant friend' Ginger, but Annie irrationally rages against any suggestion a successor for her ma could be less then diabolic.

Wilson West tells Eric that Billy is his son, unplanned but not unwanted, whose teenage mother died giving birth to the angel, which his parents help him raise. Dating privileges are maintained 'for observation'. Michael Towner bravely owes up being the one who accidentally hit Mary when she dashed after Annie, who realizes she's the guilty one but only tells off Matt's overprotective vindictiveness. Sign language in a deaf-run restaurant helps Matt patch up with Heather. Jimmy Moon dumps Lucy on account of her endless hair wining. Charles Jackson nearly lost hope Annie would turn round and Ginger imposed 'a break', but both women come to their senses after some surprising 'counseling' and fibs. Mary is released home, but recovery up to basketball level is far from certain.

Eric suddenly decides to celebrate his and Annie's 19th anniversary with a vow-renewal ceremony to make up for their spartan wedding; meanwhile, murder-victim's widow Nora Chambers tells him she wants to meet her husband's unrepentant killer Martin; Wilson West has been trying to help Mary all summer, but she only gets ruder and refuses to try to walk without crutches; Simon worries that the attic won't be ready for him to move into before school starts; Matt fights jealousy over Heather's Canadian houseguest; Lucy agonizes over Jimmy Moon dating another girl.

Simon can't resists reading Matt's letters and thus discovers big brother is secretly married to Heather. Eric can't resist spying on both, and thus falls into a trap. Wilson won't say 'I love you' back to Mary, who refuses to understand he'll only say that again when even more serious then with Billie's late ma. Lucy's friend, new girl at school Laurie, is extremely timid due to her verbally brutal ma, but the scolding root sits deeper.

A 'cool' schoolmate slips Matt a joint, which he politely tucks away in his shirt-pocket but accidentally loses the marijuana at home, where dad finds it dropping from Happy's jaw. Annie stops him from accusing Matt without any proof, so they agree to probe the kids individually, and their guests, even Wilson, who contrasts brilliantly with Lucy's Goth new mate Rod. Hasty hiding the evidence causes a huge misunderstanding. Annie's confession, first to Eric, then to Matt, she once 'experimented' too, backfires. Simon, exhausted from trying to teach Ruthie laundry, is furious when Matt confesses to spare his siblings drug tests. Eric's deaf rage only drives Matt away, and both men near despair, yet providence seems to intervene.

Matt gets bad news from his girlfriend, and goes to Philadelphia; Mary calls it quits with Wilson; Ruthie learns a lesson about kissing at school.

The reverends get their spouses to handle the annual two-families-day so they can go play pool. In fact Morgan arranges finally to meet his wife's ex Kevin, who turns out to be a happily remarried Vietnam vet in a wheelchair. As Eric expected, all kids want to do things without any parents, so only the youngest are dragged to a cartoon movie by the moms. Simon is excited about his first 'making out' party, yet terrified when it's time to step into the closet and probably kiss. Scott is 14 but looks 18 and tutors Lucy maths just so he can successfully treat Mary to a date, only to be kept on a string. Matt is surprised that the jazz club John dragged him to is his mate's singer career bid launchpad, unamused to be asked as support against Morgan. Lucy has her own date Rick, but chose the same cinema as Annie.

After Simon's school project volcano is carelessly ruined by brainless Ruthie, it's time for him to move to his own room. He's less happy with the isolated attic he's supposed to go to, but Matt agrees to move there and hand over his room, eager to 'move' to an out of state college anyway. Wilson calls Mary, but only to babysit Billy while he takes his date to her prom. Despite home advice, Mary performs miserably, yet Wilson returns early, having decided he only wants a girl who tells he family about Billy. Lucy desperately recruits enough big sibling support to get permission to go eat in town with two 'cool' sisters. Being driven in their car is forbidden, which turns out to be a life-saver, alas literally, leaving a guilt problem.

Matt is edgy, telling only his sibling he found an out of state summer job so he'll leave home in days, not months. Simon finds a brilliant trick to train happy for a TV pet food commercial, but there's a stage-fright complication. Mary rudely scolds Matt, unlike Wilson who leaves diplomatically, for getting physical at home, but her doctor notifies she's pregnant. Lucy cruelly keeps suitors Jimmy and Rod, who both chose Eric as career day model, dangling, but Wilson, who appreciates her help with Billie, arranges a date with Kenny, whom she may really want.

Matt worries now he's about to leave home, as self-absorbed, phone-glued Mary hasn't even got a clue what's happening with their younger siblings, nor is any use for either. Simon is heart-broken when Happy's original family head Jack Martin turns up and returns with a lawyer to claim the dog back. Eric considers his parents's surprise visit awkward and pointless as Matt won't be around to hold his valedictorian speech. The colonel however takes charge of an operation dog rescue inspired by Jimmy and Rod. Those two also undo Lucy's idiotic dumping of Kenny for being 'too perfect to be interested in her' and hold a remarkable church sermon. Matt changes his plans after a call from the colonel, learning about it and Annie's confession that Mary's pregnancy diagnosis got mixed up with her real one.

The first weekend all seven siblings are home, Eric and Annie plan to extend their child-labor scheme to baby-sitting the noisy newborns. Matt starts his new job at the Dairy Shack, but can't stick it out with the owner's son as his hostile boss, but the evening holds one happy surprise for him. Mary slips away to meet Wilson and runs into Jordan, while Lucy does double chores. Happy is neglected and Ruthie feels neglected, and Eric ignores Simon's well-read parenting tips and steals his Dairy Shack order. Which family member restores heavenly peace to the household?

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 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 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.

Robbie remains inconsolable since Mary left with Wilson. The Colonel figures she won't go to college but marry and be a mother to Billy, so he insists on a job, preferably in public service, but he nor Wilson are pleased she opts for the police or fire department. Lucy refuses to explain why she left the New York seminary, apparently after a break-up with Jeremy, and Robbie is parentally dissuaded as consoling company. Annie works out her pre-menopause frustration on Eric, and he takes it out deviously on model student Simon for just a bit of attitude. Matt loses his hospital orderly job, but soon gets another: in a free clinic with mainly teenage and young-adult mothers-to-be.

Robbie amuses sneaky cookie-thief Ruthie by nicknaming her Snookie and sets straight Lucy's far less flattering interpretation. Wilson diplomatically handles Mary's absurd blaming him for her failed fire department application after she set fire to the colonel's curtains. Despite Eric's continuous meanness, Simon acts most responsibly when a kid only he, not even a teacher, defended against school bullies mentions planning to shoot them. Eric confronts the supervisor of a firm's staff where 'pranks' extend to stealing a prosthetic arm an counsels his ex Merle on forgiveness.

Robbie offers to pay $200 rent for the garage apartment if it ever gets finished. However, the siblings all want it, so Matt is promised a switch with his room and the others are jealous. Billy clearly pretends to be 'really' sick to make Mary stay with him and perhaps become his mama. Lucy promises handyman Ray Rickey work on the garage apartment, but the crook fakes a fall and has a leech-lawyer waiting.

Robbie introduces Lucy to his friend Hugh, feeling she should date again, but gets jealous enough to separate them with lies. Matt stands up against the free clinic's staff and gets Hank to overrule Dr. Kent's diagnose-and-operate routine. Feeling incompetent as a waiter at Pete's Simon resigns, but he gets promoted because of his business-planning skills. Cued by Billy via George, Wilson and Mary (who is failing in firefighter training) realize it's time to decide whether to commit to becoming a family.

Insecure Robbie hides his budding rebound-affair with Lucy. Wilson is deeply hurt when he finds fickle 'bride' Mary kissing fire-department coursemate Ben Kinkirk. Simon doesn't enjoy bully-mate Rick's girl abusing him as excuse to dump him. Annie's flippant advice nearly wrecks pupil Christy Parks' parents' marriage, yet she resists help even from Eric.

Robbie and Lucy gather the courage to tell everybody about their affair, only to find they all knew and don't really care. Without the thrill of sneaking, their first date fizzles. Ben Kinkirk and Mary both pass the firefighters course, but their meeting on whether to celebrate with classmates messes up Mary's reconciliation with fiancé Wilson., and Billy's questions make Wilson decide against her plan to elope. Matt discovers that Hank and Julie are planning a divorce, and Eric and Annie try to find out why and see if they can help fix it.

Wilson is amused that all the Camdens call him after Mary's sudden return home, but wants her to tell them what happened. Robbie makes clear he's no longer interested at all in her or Lucy, having found a potential bride. The siblings however are furious when their wayward sister gets the royal treatment from their mother, while their better behavior yielded nothing. It's the last straw when the garage apartment they all want is thrown in, so they squat. Annie declares a war of attrition on them. Eric cowardly keeps out and hopes his sermon on the prodigal son may smooth things, but everyone feels targeted.

The next Valentine's day, Robbie prepared a surprise for Joy. Mary meanly supposes the hotel she overheard him contacting by phone means another sex trap. Joy, who assumed the butler to be away like her father really is, isn't discouraged, but bitterly claims Robbie doesn't love her truly because he refuses to risk getting intimate. Matt contacts all his 'true lovers', wondering why he never stayed hooked up. Lucy again assumes Jeremy, who is back in town and double-dating with Mike, wants her back and pretends to have a date. Mary is shocked to see Wilson moved back and goes steady with her former school friend Corey Conway. Simon gets permission to let his hot senior date Maria 'help babysit' and gets her cute kid brother Jake to spare Ruthie dateless embarrassment.

Lucy and Kevin see a new doctor for their pregnancy and they have different opinions of her. Ruthie becomes interested in Martin's friend and starts wearing makeup and acting older. Charlie, the new father of Leanne's baby, is having a hard time and wants out of parenthood, so Eric enlists the help of an old, dear family friend.