When her father accepts a promotion overseas in Japan , high-spirited 16-year-old Holly has no plans to head to Japan with him. She decides she'd rather live in the New York City with her "straight-laced" sister, Valerie. In the opener, Holly's attempts to prove herself a perfect roommate backfire when she misinterprets a remark about Feng Shui and rearranges the apartment. To make matters worse, Holly jeopardizes Val's job with a marketing firm when she disrupts a promotional event featuring skateboarder Tony Hawk.

Holly and Val plan a day of at the spa, but Holly finds herself in a 'muddy' situation when she sneaks out of the spa without Val's knowledge in order to meet J.C. Chasez from *NSYNC. Holly must somehow get back inside after being denied re-entry by a security guard. Being Holly, you know she always finds a sneaky way to do things, so she climbs in through a window landing in a mud bath with a naked lady! Meanwhile, Jeff and Gary have an afternoon of male competition after Gary calls Jeff old.

Val has trouble adjusting to Holly's care-free attitude, so she makes her follow a strict set of rules. Holly does her best to follow them, and realizes that she just can't do it. This leads Holly and Val ti the conclusion that Holly is nothing like Val, which is why it is hard for Holly to adjust to the rules that Val has carefully thought of and made up. So Val and Holly question why they ever became roommates.

Holly and Val battle over the possession of a stuffed teddy bear they both cherished during their childhood. But when the struggle for the bear becomes too much, the girls agree to give the critter to a little girl in the building, though after they discover she is abusive and destructive to their childhood treasure, they join forces to regain the bear.

Val tries to ease up on being an authority figure to Holly, but her patience is pushed to the limit when Holly and Gary take off for a wild party on Long Island without letting anyone know.

Holly becomes smitten with a young man, Kyle, who is leading a protest movement to allow the zoo's performing parrot to retire, but things fly out of control when Kyle is so inspired by Holly's passion for the cause that he kidnaps the parrot. Meanwhile, Val plays matchmaker for a customer who reveals she has a crush on someone in the restaurant, until it is revealed that the object of her affection is Jeff.

Gary feels left out when an old female friend comes to visit Holly, but Holly gets a surprise when she catches the pair making out. Meanwhile, Jeff is bummed when he discovers that Valerie still sleeps in an ex-boyfriend's sweat shirt.

Holly lands a job at a copy shop where she thinks her new co-worker, Jake, is interested in her, but when she takes Jeff's advice on how to handle the situation, she becomes the laughing stock of the store. Meanwhile, Val is nervous about landing a new account and impressing her prospective new client.

Determined to start their own Thanksgiving tradition, Val and Holly cancel plans with their relatives, claiming that Holly is sick. However, the girls' happy day goes awry when the family arrives at their apartment to surprise them. Meanwhile, Jeff and Gary go on a mission to find the perfect turkey for Val.

Holly has a major crush on a cute college guy named Evan and he's been coming in everyday at "Copy That" to get some coffee but Holly gets a chance to actually know him when she "accidentially" takes Evan's cell phone and gets invited to a college party to swap phones. Gary wants to come too, but Holly doesn't want him to interfere. However, despite Holly's wishes, Gary shows up at the party as a co-ed to get in with the college girls. Meanwhile, Val starts to get a little competitive at Scrabble.

Holly becomes pals with Jeff's ex-girlfriend, Dana when they both go to a U2 concert with Jeff, even though Val warned Jeff and Holly not to go with Dana, and Jeff never even wanted Holly and Dana to be friends. Meanwhile, Gary saves the life of a real-estate magnate at the concert.

While Jeff is out of town, Holly takes Val out on the town, but the female bonding stops when Hunter, a guy Holly has her eye on, makes a pass at Val. Things get worse when Hunter's jealous girlfriend comes looking for Val.

Holly volunteers to fill in at Val's office over spring break, but the girls clash over the tactics Val should use to land a promotion over a competitive colleague; Holly believes in playing dirty and kissing up to the boss and Val thinks her hard work and dedication will get her noticed.

On the most romantic day of the year, Holly jumps to the conclusion that Jeff is planning to propose to Val and Gary lands a date with a great girl, but the Valentine's Day pressures overwhelm him and he insists Holly double date with them.

When Holly sets her sites on buying an expensive sweater, Jeff agrees to hire Holly as a waitress but ultimately regrets his decision when Holly turns the restaurant upside down and even causes the chef to walk out.

Valerie breaks up with Jeff after he says he doesn't want to get married, and she tries to bury her pain under a veneer of optimism. Holly then tries to get her sister to drop the act and face up to her pain.

Holly ditches school with Henry and borrows Val's car, but is shocked when she returns from the beach, to find the car gone! She tries to cover it up and act like it is gone, but Val soon finds out. They have a talk, and Holly admits to it, while Holly tells Val she has learned that Val takes $20 out of her allowance each week. Holly is mad, but then she finds out that, along with $30 of her own that Val puts in, that $20 is in a secret account for Holly's college.

Jeff is trying to find a new job, when his dad decides to close their resteraunt.

Upon learning that Val has a reputation for being antisocial at work, Holly encourages her sister to mingle with her colleagues. However, an evening out becomes fodder for office gossip when Val finds herself in a compromising position with her boss Vic. Meanwhile, Jeff meets the attractive Olivia-but is shocked to find out that she is Gary's mother.

When Holly meets Henry's older brother, Noah, she instantly assumes that he and Val would be a great couple. Despite Henry's asking of Holly not to fix them up, Holly fixes Val and Noah up anyway, and eventually finds out why Henry asked for them not to be fixed up.

Val and Holly meet a resident who would've got their apartment 5 years ago, but got a smaller one. So she threatens to evict them. Meanwhile, Gary thinks Holly forgot her birthday when she gives him a cheap present. So Gary gets mad at Holly for it, not knowing that that wasn't the only present.

In the first season finale, Val gets home from work only to find Holly and Henry in Holly's room---with the door closed! Val worries that Holly and Henry have slept together. She lectures Holly about sex. But when Holly comes home from the movies, she walks in to find only Val and Jeff in the shower together, making Val look like a hypocrite. Gary keeps ditching Holly to spend time with his girlfriend.