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.
As the office gets ready for Michael's final day at Dunder Mifflin, Michael doesn't tell anyone that he's leaving a day early. Meanwhile, Deangelo accompanies a nervous Andy on a visit to one of Michael's old clients.
Dwight's too-realistic fire alarm gives Stanley a heart attack. When he returns, Michael learns that he is the cause of Stanley's stress. To remedy the situation, he forces the office to throw a roast for him.
Michael invites Jim and Pam and Andy and Angela to a couples-only dinner party, where they witness Michael and Jan's extremely dysfunctional home life. Dwight finds a way to invite himself, too.
Dwight prepares for a marriage proposal and hires an assistant for his assistant, Andy auditions for a singing program, Darryl tries to leave his job without a fuss, and Pam has second thoughts about Jim staying in Scranton.
Pam is forced to deal with an embarrassing injury for Andy the night before her wedding, while Kevin deals with the loss of his dress shoes on the morning of the ceremony.
Michael finally finishes his movie "Threat Level Midnight" and screens it for his employees at Dunder Mifflin, but Holly is less than enthusiastic for his finished product.
Michael plans to propose to Holly the day of the Dunder Mifflin garage sale, but Holly may have to take an extended leave of absence to Colorado because her father is sick.
The Office travels to Niagara Falls to celebrate Jim and Pam's wedding under strict orders not to mention Pam's pregnancy. Michael, Dwight, and Andy all want to hook up with guests at the wedding.