A new school year finds Simon, Matt, and Lucy living the single life again.
Mary treads on shaky ground when she loses her job and gets caught in a lie.
Each member of the Camden household is either the victim or the perpetrator of the classic Friday night “stand up.”
Lucy discovers the boy she wants to kiss spent time in a mental hospital.
Mary’s new friends at work could be turning her toward substance abuse.
Matt, Simon and Lucy try to save Mary from ruthless debt collectors.
Mary’s sent to live with her grandfather in Buffalo against her will.
The Camdens are torn apart by harsh rumors after Mary’s departure to Buffalo.
Simon’s new friends target Lucy and Annie as victims of their harassment.
Despite the disapproval from the rest of the family and his own hesitations, Eric takes in Mary's ex-boyfriend Robbie Palmer (Adam LaVorgna) to live with the Camden's for the night after learning that he's homeless. Matt also shows up unexpectedly after being kicked out of his apartment by John, who needs quality time with his girlfriend. Meanwhile, Mary calls home again and hears Robbie's voice on the other end and assumes he's dating Lucy now. Also, John proposes to his girlfriend Priscilla in front of Matt.
Robbie is such a good houseguest that Annie and Matt feel underappreciated.
Mary sneaks back to Glenoak and Eric is right on her tail.
Lucy gets jealous when her new love interest asks her to set him up with another girl.
Mary's feelings for Robbie resurface when she inadvertently finds out he has a secret date for Valentine's Day, and the whole family schemes to uncover the mystery woman. Meanwhile, with the exception of Lucy who has a date with Jeremy, the other Camden kids feel deflated when their Valentine's plans fall through and they end up stuck at home celebrating Sam and David's second birthday. Lucy and Jeremy's first date does not go as expected as they both keep on running into Lucy's ex-boyfriends. Although all's well that ends well by the end of the episode for everyone.
No one thinks Simon will do the right thing when he finds himself alone with an attractive, older girl.
Robbie is ecstatic when his long-lost father (guest-star Alan Thicke) who is a dead-beat dad appears out of the blue. Although, Eric and Annie distrust the dead-beat dad's motives. He also convinces Robbie to move out with him; against Eric's wishes. Meanwhile, Ruthie turns to Mary for advice on how to get around their parents rules when wanting to buy a makeup kit that they said 'no' to. Also, a very convinced Annie worries when Lucy starts having a relationship with her friend's freewheeling ""unmotherlike"" mom. Also, Simon develops a bad attitude with his mother when not wanting to do his school work, but wants to hang out with his friends.
Matt fears a therapist will reveal his inability to succeed as a doctor.
Robbie spends time with a girl that looks identical to Mary.
Annie discovers that the particularly flirtatious mother of one of Lucy's friends, Serena is seeing Eric for therapy sessions. Annie strongly requests that he refers her to someone else. Annie then has to deal with the guilt over her jealousy-induced interference between the two. Also, Simon is mortified when word gets around school over the fact that he's a virgin. Annie had shared the details of Simon's sexual inexperience with his ex-girlfriend's (Sasha) mother, Rita. Meanwhile, Matt struggles about telling Robbie he's interested with his ex-girlfriend, Cheryl. Lastly, Robbie is also hiding a secret from Matt that involves his ex-girlfriend Heather.
The Glenoak Community is making a big fuss over a petition that is protesting the apparently unfair firing of one of Ruthie's teachers, Mrs. Miller at her private school. Although, Matt knows the real reason of why she is leaving since she has been to his hospital after being diagnosed with advanced breast cancer, which leads to the embarrassment of many of the petitioners--- including Simon and Lucy when they encounter her brother who's a teacher at their high school. Also, Annie's father Charles drops by at the Camden's for a visit. Annie is then surprised and shocked when her father passes on news to Eric--- to tell her that she has a sister, Lily.
Robbie adopts a hands-off policy when Mary comes home for the summer.
Lucy discovers the truth about her boyfriend’s past with Mary.