Sparks fly between Jacqueline "Jack" Barrett and David "Jill" Jillefksy when they meet in New York---after she leaves her unfaithful fiancé and his girlfriend asks him to move in with her.

While up for a promotion, Jack's ex-fiancé shows up at her job and asks for her forgiveness and a chance at reconciliation. As Jill and Elisa try to adjust to living together, Jill's job is in jeopardy if he doesn't find a prototype toy he borrowed and lost. Meanwhile, Mikey moves into an unwilling Barto's apartment.

In an attempt to meet new women, Jill and Barto throw a party. Jill invites Elisa thinking she'll feel too uncomfortable to go, but she shows up anyway and causes him to feel jealous the whole night while Barto spends his night trying to talk to Audrey. Meanwhile, Jill tries to have a one night stand to get over Danny.

Jill's boss, Mr. Ashton dies before he can give Jill a promised promotion. Jill insults his new boss during a business meeting. Jack takes a job at a dirty restaurant in order to get a story on poor restaurant sanitation. Audrey is afraid to break up with her director boyfriend after he gets her an important role. Jack tries to help Elisa and Jill get back together but Elisa can't help feeling that there is something between Jack and Jill. Jill contemplates leaving Major Toys but later makes peace with the new boss, Theodore.

While on an assignment together, Elisa and Jack get into a fight over the kiss with Jill that Jack lied about. Jill goes on a date with a woman he had a crush on in high school. When Jill starts falling in love with her, he realizes that she is not being completely honest with him and Jack realizes that she is in denial over having feelings for him. Meanwhile, Barto tries to start things up with Audrey by helping her get over her fear of singing a solo.

Jill's younger sister Abby comes to visit. Elisa goes to dinner and to a play solo. Audrey and Barto sleep together. Mikey takes Abby to a night club and Jill goes to find her. Jill and Abby have a fight but later part on good terms. Barto sees Audrey hanging out with Travis, the director again and he is crushed.

Jack agrees to have dinner with Jill, intending to tell him that she can't date him because of her friendship with Elisa, but when a new reporter, Matt Prophet, comes to WNKW, Jack cancels her dinner plans in order to work with Matt. Meanwhile, Barto's grades suffer because he can't stop thinking about his one-night stand with Audrey; Audrey begins to doubt her relationship with Travis; and Mikey attends a singles sminar with Elisa.

When Jill's co-worker Stan takes credit for his idea, Jill challenges him to a boxing match at Mikey's Office Fight Night at the bar. Jack and Matt cover the story of Jill's fight for WNKW and which causes Jill's jealousy to rise. Meanwhile, Barto asks Audrey out to celebrate a good review of her musical and Elisa feels a connection with a stranger she passes on the street.

Jill is sued for breaking up a marriage and Jack begins to doubt her relationship with Matt when Jill insinuates that Jack may not be the only lady in Matt's life. Meanwhile, Audrey frets when Barto starts hanging out with a female study buddy; Elisa continues to hunt for her mystery man; and Mikey gets an unwanted promotion that requires him to fire one of the waitresses.

Jill's suspicions are aroused when he sees Matt with another women, and he contemplates telling Jack. Meanwhile, Jill's tactless girlfriend offends Mikey.

Barto takes Audrey to meet his snobbish parents after she overhears his mother's invitation on the answering machine. Meanwhile, Elisa finally gets to man, and Jack and Jill get stuck in the laundry room, ruining their dates with Matt and Allison.

In the morning, Jack and Jill lie sleeplessly in their respective beds when a passing ice cream truck sets off a loud car alarm. Both of them run out to shut it off, but Jill must finally yank out a wire. The Ice Cream Man is so grateful that he promises to grant Jill his greatest wish. The next day, at Major Toys, Jill's boss announces that he is putting one of Jill's creations, Zantopia, into development. Jill tells the great news to Allison, who focuses on the career implications. Later, Jill becomes concerned when his boss makes changes to the project. Jack understands Jill's disappointment and sympathizes with him, while Allison thinks Jill shouldn't be upset since he is going to be promoted to vice president.

As Jack ponders Jill's passionate declaration of his feelings for her, she learns Matt has gotten an offer for a job in Washington, D.C.

Jack chooses between Jill and Matt; and Eliza swears to Jonathon that she doesn't want anything for Valentine's Day. Meanwhile, Audrey injures her leg.

Relationships become strained as Jack and Jill realize they're revealing too much about their love lives to their friends, Audrey and Barto.

New roommates Mikey and Eliza clash when she becomes too chummy with one of Mikey's dates. Meanwhile, Jack and Jill spar over saying "I love you."

Barto starts seeing the ghost of his mad school cadaver after he tries and fails to save a bystander suffering a heart attack, Jill asks Jack to pose nude for his photography class.

Elisa and Mikey find that being roommates is difficult. Elisa is a complete slob, and Mikey eats all of her food. Mikey and Elisa hire Belinda as their maid. Meanwhile, Jill leaves a key to his apartment with Jack after locking himself out for the third time in a week. Jack sneaks a peek at Jill's journal and reads about the best sex of his life with another woman. Paranoid, she asks Mikey for advice, then surprises Jill by seducing him in a new way. Audrey and Barto's relationship is jeopardized when Barto gets a new study partner, Annie. While Barto contemplates an internship in Atlanta, Audrey gets a movie offer in Los Angeles. Barto scores a top grade in his final examination and celebrates with Annie. A jealous Audrey sees them together.

Audrey's Agent strokes her infatuation with Hollywood, leaving Barto feeling neglected and vulnerable to sympathy from Annie. Meanwhile, Jack and Jill consider moving in together.