The everyday lives of office employees in the Scranton, Pennsylvania branch of the fictional Dunder Mifflin Paper Company.
Two new, young employees throw Dwight and Jim off balance; Andy returns from leadership training with a desire for revenge.
A toast at Roy's wedding leads to Pam and Jim searching their relationships for buried secrets; Dwight reacts to Nellie's mandatory charity initiative.
Andy flaunts his genealogy when he discovers he's related to Michelle Obama. Meanwhile, Darryl struggles in his new post, Dwight teaches Erin a new language to wow her boyfriend's family, and Nellie tries to persuade Pam that Jim's having an affair.
The staffers hit the road in a rented bus when the building is deemed unsafe. Meanwhile, Nellie reaches out to Andy for help in adopting a baby, and Jim uses pie to spread cheer to Pam.
It's Halloween in the office and Andy invites his college a cappella group to perform, which leads to a confrontation with his frenemy Broccoli Rob. Meanwhile, Dwight finds evidence that a madman is loose in the office and tries to track him down, and the first meeting of Jim's new job causes a fight with Pam.
Money problems plague Andy's family. Meanwhile, Dwight guests on a local radio show, so the staffers harass him with outrageous phone calls, and Kevin unearths a big secret about Oscar.
The women of the office try to teach Dwight how to interact with female clients; Angela suspects the senator of cheating; Toby convinces some of the guys to grow mustaches.
Angela goes to Dwight for help when she learns that her husband is having an affair. Stanley and Phyllis take advantage of Jim when he needs a favor, and Pete distracts Pam as she begins painting her mural.
When the party planning committee drops the ball on the annual Christmas party, Dwight gets everyone to celebrate with a traditional Schrute German Christmas. Darryl fears that Jim has forgotten to include him in the new job in Philadelphia. Pete teaches Erin about his favorite movie, Die Hard.
Pam accidentally brings lice into the office and lets Meredith take the fall, while Dwight vows to destroy the parasites. Meanwhile, Jim has a fantastic day in Philly wooing a potential business associate. Meanwhile, Phyllis, Nellie and Kevin meddle in Darryl's love life.
Clark brings an espresso maker to the office. Dwight and Clark pretend to be a father-and-son to land a sale. Darryl goes on an interview at Jim's company, where Pam drops by unexpectedly.
Dwight tries to stop Darryl from moving to Jim's start-up company. Jim misses his daughter's first recital, to Pam's dismay. Nellie spills the beans about Pete and Erin.
Dwight is tasked with hiring a part-time salesman to be Jim's substitute, so he rounds up a supergroup of his cronies, including his oddball beet-farmer cousin, Mose. Pam is left wondering who her new deskmate will be. Erin seeks her birth parents with help from Pete.
Pam’s warehouse mural is defaced. Darryl has difficulty dealing with the Jim's cleanliness habits in their apartment. Angela grudgingly allows Oscar and Kevin to attend her son’s first birthday party.
The staffers pair up as faux couples to score a Valentine's Day discount at a mall. Erin tells Pete that she'll break up with Andy when he returns, but Pete has his doubts. Jim and Pam socialize with the documentary's soundman.
Pam interviews for a job in Philadelphia, but her potential manager reminds her of her former boss, Michael Scott. Dwight acquires the help of Angela in order to give his elderly Aunt Shirley a bath. Meanwhile, Andy attempts to make Pete and Erin feel uncomfortable.
The adventures of Dwight at his family beet farm and bed-and-breakfast come to light. Here, he and his siblings receive a surprise inheritance. Back at the office, Todd Packer tries to atone for a lifetime of boorish behavior.
Everyone in the office is excited when promos start running on TV for the documentary. Dwight makes Angela jealous when he starts dating a brussel sprout farmer. Meanwhile Jim has a big meeting with Major League baseball player, Ryan Howard.
The elevator goes out at the office, forcing everyone to use the stairs. Dwight forces Stanley to make a sales call. Pam and Jim talk to Nellie and Toby about relationship problems. Angela supports her man.
Dwight and Angela participate in a paper airplane contest and compete against each other. Meanwhile, Andy prepares for a potential acting job, and Jim and Pam utilize new skills.
Dwight becomes regional manager after Andy quits his job, Jim dedicates more time to his Dunder Mifflin job to save his marriage, and Angela has problems with her new living arrangements after her breakup with The Senator.
Jim convinces Dwight that he needs to choose someone to act as an Assistant to the Assistant Regional Manager; the two subsequently hold tryouts for the position. After her daycare turns away her child, Angela is forced to bring her kid to work. Andy auditions for "The Next Great A Cappella Sensation".
One year later, Dunder Mifflin employees past and present reunite for a panel discussion about the documentary and to attend Dwight and Angela's wedding.