Will's poker night with his buddies gets interrupted by the unexpected arrival of Grace, who has once again broken up with her boyfriend and arrives to spend the night--much to the displeasure of Will's friend Jack, who was planning to move in temporarily while his own apartment has new flooring put in. Will talks Grace into finally leaving her boyfriend for good, she marches off to confront him, but when she returns to announce that she has accepted a marriage proposal, Will risks their friendship by telling her what he thinks.
Will and Grace's friendship becomes strained when he encourages her to find a place of her own--and then quickly discourages her idea to move in with him. Meanwhile, Jack's eccentricities are driving Will out of his mind.
Tensions escalate between new roommates Will and Grace when Grace has a giant hissy fit about her bathroom and insists on merging the adjoining bathroom without Will's consent, despite the fact he owns the apartment. Meanwhile, Will helps Jack with his r?sum
Grace reluctantly agrees to decorate Harlin's new apartment and she gets carried away with the cowboy theme. Meanwhile, Jack plays the diva role to the hilt when he auditions for a one-man show ('Just Jack') at a nightclub, with staging advice from a reluctantly intrigued Karen.
Will and Grace plan to spend a serious Halloween together watching Ingmar Bergman movies at home--until Harlin drops off his over-eager kids at their place when he's called away on business. Meanwhile, Jack convinces Karen to accompany him to the downtown parade where she becomes an honorary drag queen.
When Karen goes on vacation for a week, Grace hires Jack as her assistant. After Jack discloses Will's past affair with a 'client,' Grace worries that Will is keeping secrets from her. Meanwhile, Karen ponders leaving her husband and turns to Will for some legal help.
Grace claims that the reason she's not dating is that she's having too much 'fun' with Will--so she proposes that they try their best not to have fun. Meanwhile, Jack is seeing stars over seeing an IRS agent, so he enlists Will's help.
Grace has the opportunity to buy her studio space from her building's owner. Since savvy lawyer Will is a tough negotiator, she asks him to help her with the offer. Grace thinks the whole deal will be a piece of cake, so she's shocked at the tactics Will has to use to get the price down. Meanwhile, Jack decides to become a massage therapist and asks Karen to be his 'guinea pig' for his training. Although reluctant at first, Karen discovers that Jack has a real knack with her back--and wants him all to herself.
After Grace defies Will's wishes and brings home a puppy, Will can't resist the pooch and begins to treat him like a newborn baby. Meanwhile, Jack and Karen worry about the dog's effect on Will and Grace and insist that the new parents go out for a night on the town.
After Will installs a new heating vent in the apartment, he and Grace become obsessed with eavesdropping on the marital problems of the couple downstairs. Meanwhile, Jack's new career this week is playwriting and he enlists Karen's help in staging a play to bring them back to reality.
Grace and Jack, who have discovered a shared love for figure skating, get tickets for a hot ice show on the night they were planning to celebrate Will's birthday. An ice show is the last place Will wants to spend the evening, but he goes along to please his pals, accompanied by an even more reluctant Karen.
While Grace is pulling her hair out over an important showcase attended by critics, Will hires a maid whose presence changes Grace into a creative dynamo. Meanwhile, Jack pretends to be a lawyer to impress a handsome suitor.
Grace gets a visit from her critical, over-the-top mother, a would-be star whose propensity for breaking out into show tunes and impersonations dismays her daughter -- and delights Will, Jack and Karen. She also wreaks havoc by suggesting Will and Grace wed, despite their sexual differences. When Will winces at the fantasy of committing to anyone who needs to be the star of a relationship, it's an eye-opener for Grace, who sees she's more of a chip off the old block than she imagined. Meanwhile, Karen thinks she might be pregnant so Jack helps her take a pregnancy test.
Determined to mend their relationship, Grace surprises Will by inviting his estranged, older brother to Jack's birthday party. Will gets angry, but Grace may be too attracted to big brother to care.
Grace incurs Will's wrath when she spills the beans about her fling with his brother Sam. Karen goes into serious caring-friend mode, helping Grace sort out her feelings for both brothers and helping to guide Jack through the terrors of turning 30.
When a good-looking but sexually ambiguous new tenant moves in, both Will and Grace vie for his attentions until the competition grows so nasty it threatens their own relationship. Meanwhile, Karen has to fire her driver.
The gang roughs it in Karen's Vermont cabin in order to take Will's mind off what would have been his anniversary with his ex-boyfriend, Michael. Grace rekindles a romance with an old high-school flame and tries to hide the fling from Will. Meanwhile, Karen's culinary efforts go up in smoke, as does Jack's attempt to cheer Will by dragging him to a gay pub.
When Grace's job forces her to work overtime, Will feels utterly neglected. He seeks solace in the company of a new neighbor, Val, a recent divorcee who matches Grace quirk for quirk. At first, Grace seems oblivious to their camaraderie until Karen warns her of impending danger. Meanwhile, Jack is annoyed that he has to perform community service for slapping a meter maid, but he's even more horrified at the uniform he has to wear.
When Jack's gym membership is taken away, Grace suggests -- to Will's horror -- that Jack use the guest pass to Will's gym. When Jack joins Will to work out, Will becomes embarrassed to be seen with him. Meanwhile, Grace has a heart-to-heart with Karen.
A successful and arrogant New York publicist hires Grace to decorate his house with the condition that she fixes him up with Will. But there's a problem: Will can't stand the guy. Meanwhile, Jack uses Karen to teach Will how to kiss someone he finds unattractive.
When Rob and Ellen admit that they don't have fun playing games with Will and Grace because of Grace's competitive nature, Grace works to change her image. However, as Grace loses her competitive edge, Will's emerges and he convinces his partner to care only about winning. Meanwhile, Karen saves a workman's life after learning how to administer CPR from Jack.
Will is stunned to discover that Grace is dating her ex-fiance Danny once again, but he chooses not to interfere after he's accused of being meddlesome. Meanwhile, Jack agrees to take a walk down the aisle with Karen's combative maid, Rosario, who needs a groom to help her smooth out some immigration problems.