A few interns who stayed at Dunder-Mifflin over the summer end their internship. Michael announces some potentially damaging gossip about an employee to the rest of the office, then starts to spread false rumours about others to cover up what he has unwittingly revealed.
David Wallace comes bearing the news that not all the staffers will receive a raise this year. Jim pushes Dwight to the limit and causes him to form office alliances. And Pam decides she wants only cash as a wedding gift.
The Dunder Mifflin staff head to Niagara Falls for Jim and Pam's wedding, with the understanding that her pregnancy is a forbidden discussion topic, but Jim's slip of the tongue prods Michael to attempt damage control.
Michael becomes convinced that an insurance salesman visiting the office is a part of the mafia, and Dwight and Andy accompany Michael to a meeting with him. Meanwhile, Kevin accidentally cancels Jim's credit card, while Jim and Pam are on their honeymoon in Puerto Rico.
Jim and Pam return from their honeymoon and discover that Michael is dating Pam's mother, which infuriates her. Meanwhile, Dwight tries to install a recording device in Jim's office, by giving him a wooden mallard as an apology for their long rivalry.
Michael and Jim head off to a meeting and Michael comes back soaked after having fallen in a koi pond. Meanwhile, Pam and Andy, as the two worst salesmen in the branch, have to go cold calling for sales.
Jim and Pam finally go on a double date with Michael and Pam's mother Helene on Helene's birthday, which takes a dark turn when Michael discovers just how old Helene is turning, and breaks up with her. Meanwhile, Dwight offers to do nice things for all the members of the office so that they will owe him a specific favor, but Andy ruins his plans.
Rumors spread that Dunder Mifflin is in financial trouble, so Michael tries to distract the office by having everyone play a murder mystery game called Belles, Bourbon, and Bullets. Meanwhile, Andy uses the game as a way to ask out Erin, but fears he may have asked out Erin's character, instead of Erin herself.
Michael speaks out of line at the Dunder Mifflin shareholders meeting and creates a big problem for management, while Jim discovers that nobody in the office thinks he's the "real" boss.
Michael and Erin meet "Scott's Tots", a group of local teenagers whose college tuition was promised in one of Michael's grand delusions ten years prior. Meanwhile, in Michael's absence, Dwight convinces Jim to start an employee-of-the-month program with the intention of sabotaging Jim.
Michael gets upset when Jim promises Phyllis that she can be the office Santa, but the office Christmas party may be overshadowed by some bad news from David Wallace.
Michael hates the changes that Dunder Mifflin's new owner is implementing, so he turns to David Wallace for advice. Jim and Pam find the perfect day care center, but Jim's mistake threatens to ruin the interview.
Sabre's CEO wants the Scranton branch to have one manager, and Michael voluntarily steps down and lets Jim become the boss when he finds out that salespeople make more money. However, he soon comes to regret the decision.
Pam’s contractions begin but she and Jim are determined to wait it out as long as possible so they can have more time at the hospital. Meanwhile the rest of the office tries to distract Pam from the pain with food and entertainment.
Michael thinks he impressed Jo only to discover someone else in the office caught her eye. Meanwhile, Dwight makes trouble on Jim's first day back from paternity leave. Andy and Erin have an interesting first date.
Michael gets kicked out of the bar when he pulls out all the stops to impress a friend of Jim and Pam's. Meanwhile, Andy and Erin do their best to keep their relationship under wraps. Dwight rethinks his pre-natal contract with Angela.
Andy pulls out all the stops to give Erin a memorable Secretary's Day. Michael reluctantly takes Erin out to lunch and lets slip about Andy's relationship with Angela. Meanwhile, Oscar circulates a video he created that compares Kevin's voice to Sesame Street's Cookie Monster.
Pam and Jim work on their first sales pitch together to Donna, the manager of a local restaurant. But Michael keeps misreading the signals she's putting out. Meanwhile, Dwight encourages Kelly to try out for the minority training program.
Michael suspects Donna is cheating on him and puts P.I. Dwight Schrute on the case. Meanwhile, Andy is frustrated when no one takes his customer's complaint seriously.
Michael is surprisingly cheerful after learning some bad news about Donna. The new parents, Pam and Jim, have trouble staying awake in the office. Meanwhile, Angela takes matters into her own hands when Dwight refuses to honor their contract.
The press finds out that Sabre’s printers catch on fire. Jo shows up to the office in hopes of finding out who the whistleblower is. Everyone suspects Andy, who adamantly denies he leaked the information.