James struggles to write an important speech to keep himself from being fired by Caitlin. Meanwhile, Paul is worried that Caitlin wants his office; she ends up moving into Mike's. And Nikki breaks up with Mike.

Caitlin implants secret background checks on all City Hall employees. Mike, Stuart and Carter break into her office to see the files. Caitlin goes to Nikki and Janelle's girls' night out. The mayor is offered a part in a movie filming in New York.

Mike tricks Nikki into seeing a couples counselor. The mayor takes an eighth grade test after being challenged by junior-high students. Stuart attempts to join Carter's gay gym to meet women.

The mayor considers quitting the senatorial race, teaming Mike and Caitlin to stop him. Carter becomes a kept man, and Paul and James scheme to play a good practical joke on Stuart.

Claudia's mother kicks Paul out of his house so he moves in with Stuart and Carter. Nikki dates the office's new young male intern. And Mike courts a wealthy socialite to donate money when the mayor's campaign runs out.

Mike and Caitlin agree to share the mayor on odd/even days. On Caitlin's day, Mike ""borrows"" the mayor to visit a kid who fell in a well. Unfortunately, they're 20 minutes late and the mayor falls in the now vacant well. Carter puts Rags in doggie day care. Paul appears on Who Wants to Be a Millionaire and wins $1,000,000. Stuart negotiates with firemen.

A newly rich Paul thinks Caitlin is hitting on him. The mayor wants a senator's endorsement and invites him, along with his staff, to Gracie Mansion for Thanksgiving. The senator thinks that Mike and Caitlin are a couple so they must share a room. Stuart and Deidre are back together.

Paul has invested in a politically themed restaurant. Mike struggles to run the city while the mayor is out of town. Deidre is stalking Caitlin a la ""Single White Female.""

Mike celebrates his five-year anniversary working for the mayor by taking Caitlin and going on a joyride with the mayor's '66 Mustang. Nikki and Carter accuse each other of being vain when City Hall ID photos are taken. The mayor wants to rekindle his romance with Janelle. Caitlin's busy schedule forces James back to speechwriting; he hires Deidre to be Mike's new secretary.

Mike invites Caitlin to his Christmas party as his only guest but his plans at romance are spoiled when she arrives with a date. Paul finds John McEnroe's headband in the City Hall clothing drive box. James finds a second job as a suicide hotline operator. Stuart installs a chin-up bar in the mayor's office, which the mayor promptly injures himself on.

The mayor struggles to find a date for a mayor's conference. Mike goes out with Caitlin's sister, making Caitlin jealous. Stuart tries to join Nikki, James and Janelle's art class to see nude women. Paul is upset that Carter makes more money than him.

Paul's cheap dentist puts braces on James instead of removing his infected tooth, causing problems in James' date with the new mail girl. The city's raffle to raise money for the Big Buddy program is screwed up when Paul skimps on the raffle tickets. Stuart and Carter blackmail Caitlin to decrease their workload.

After eating some of Rags' dog food, Paul develops a rash before he appears on ""The View."" Nikki helps him discover the wonders of makeup, though. Stuart tries to convince James that he's gay. Mike hires a hotshot director to film the mayor's Senate commercial, unaware that Trevor is Caitlin's ex-husband. After the commercial turns out to be a flop and Mike fires Trevor, Caitlin accuses him of being jealous. When a talk with Nikki persuades Mike to express his feelings for Caitlin, he sees her and Trevor in a heated embrace.

To quell a protest by senior citizens, Mike plans to get the city's first woman voter to vote for the mayor. When Mike finds out that Trevor isn't really British, he must decide whether to tell Caitlin or not. Carter protests anti-gay discrimination in an apartment building. James and Paul fight over a ""hey guy.""

While a reporter visits City Hall to do a story on Paul, the mayor thinks she's really there for him. Mike thinks Carter's boyfriend is hitting on him. The staff looks for good samaritans for a dinner. Stuart tries to convince James that he's getting fat.

Mike has a meeting with a tomato stand owner who refuses to move his stand so that the city can build a new performing arts center. He ultimately enlists James to compete against the man in a ""pig-off"" to decide whether the stand will stay or move. The mayor befriends a rapper who sampled one of his speeches in a song. Paul and Deirdre have memories of having sex at a concert 20 years before, driving Stuart jealous.

Mike helps the mayor deal with his feelings when his father unexpectedly dies. James thinks Caitlin has a crush on him. Paul's magic eight ball proves helpful to the staff.

With the President coming to visit City Hall, Mike is upset when Caitlin gets to meet him instead until plans change. The rest of the staff gathers at the bar, where Caitlin joins them. Nikki and Carter bet on who can pick up more women. Stuart tries to get Caitlin drunk; he succeeds and she leaves a drunken message for Mike. Paul tries to get James to help take his picture with the President.

The mayor prepares for a three-day trip across New York on his new campaign bus. Paul and James grow mustaches when they think that Carter's gets him the best assignments. Nikki becomes a female version of Stuart when she consults him for dating advice. After Mike discovers that Trevor has asked Caitlin to marry him again, he accidentally hits him with the bus. Mike and Caitlin kiss but their session is interrupted when Mike reveals he was deliberately aiming for Trevor.

While Michael and Caitlin fly to San Francisco, Stuart joins Carter for a protest and the mayor tries to have a light bulb changed.

Caitlin prepares to marry Trevor and elopes to Paris, where Mike follows and reveals that he loves her. James becomes angered with the mayor when he receives an undeserved war award. Stuart asks Nikki to pose for a ""charity"" swimsuit calendar.

Mike and Caitlin return from Paris as a couple. Caitlin wants more than a physical relationship, so Mike bets her that he can resist her for a week, while tries to break his willpower. The mayor falls in love with Rags after filming an animal rights commercial with him.

Mike discusses his attempts to have sex with Caitlin with his new therapist. Nikki's new boyfriend is too likable. Caitlin isn't in the mood when Mike is. A reporter accuses the mayor of being involved in organized crime; Nikki's boyfriend turns out to be a mobster who has been getting the office staff to do favors for him. Mike weighs giving his friends up, but ultimately throws himself on his sword and takes all blame.

Mike and Caitlin have sex. The staff works damage control but Mike ultimately fires himself to save everybody else. The staff says their goodbyes at the bar. Caitlin promises Mike that she's not going anywhere. Mike says goodbye to the mayor and walks out of City Hall for the last time. Six weeks later, Mike turns up as an environmental lobbyist in DC.