The cast shows their singing skills as the express their feelings about Valentine's Day. Simon starts dating another gal. The twins celebrate their birthday.

Rosie moves in with Simon and remodels his studio, while keeping her apartment as a front, but that proves unpractical. Simon insists on telling their parents they'll get married, but after graduation. When Simon announces that he is going to come and bring bad news, dad and Lucy falsely 'hope' it's their break-up. They disagree on what to offer single women, except a 'church social', which Martin accepts and brings Meredith as their first date. Kevin eagerly accepts Joanie's invitation to her 'mom and I' class, where the sensitive hunk is an instant hit. The parents disagree whether to forbid Ruthie going out with 'too mature' Jack, so she gets Martin to set her up with honor student Sam Walker.

Simon bursts his startled parents' malicious bubble: he's not dumping Rose, she moved in. When Simon accepts 'too easily' to give Rosie her marching orders -which she ignores- as they pay for the apartment, they hoped he wanted an excuse to break up and be with Sandy, who they prefer, this time partially true. The twins announce they have each found true love. Ruthie tries to get rid of Sam Walker, but neither Eric nor Martin agree to do her dirty work. After church teenagers class girl Lizzie Wheeler admits an unwanted pregnancy, Lucy doubts her decision to stay in pastoral work and envies Kevin's obviously excellent home parenting, then Lizzie changes her story. Rosie sets an ultimatum. Martin tells Lucy he'll become a father.

Simon isn't amused that Rose pulls all the stops out hosting a luxurious dinner to impress her Italian ex, Umberto 'Bert' Lanzo, who left her at the altar. He jests about wanting her back, or is he serious - and who is the mystery girl Simon agrees to talk to immediately but covertly? The Camden parents, are not amused that Ruthie's long-awaited cellphone does nothing for her social life. Eric urges the boys to call her, helped by unwilling Peter Petrowski's dad George 'Vic' Vickery and Kevin. Benjamin Bainsworth, meanwhile, finds her number and works up the courage to call after a year.