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.
While on lecture tour to other Dunder Mifflin branches, Michael and Pam discover that Jim's ex-girlfriend Karen is pregnant. At the office, Andy falls for a prospective client, and Jim and Dwight try to set up Kelly's birthday party.
Michael holds a lonely hearts party on Valentine's Day at the office, hoping that he will run into a woman he met earlier that day at a blood drive. Meanwhile, Jim and Pam have an awkward lunch with Phillis and Bob Vance.
Michael asks Dwight to be the scapegoat for one of his business ideas that backfired badly on him. But when that idea has an unexpected positive upside, Dwight still takes credit and Michael becomes furious.
Michael gets upset when he gets a new boss to act as a buffer between him and David Wallace, and he gets even more upset when he disbands the Party Planning Committee and cancels Michael's fifteenth anniversary party.
Dwight chooses loyalty to Dunder Mifflin over loyalty to Michael, which leads to a bitter battle between Michael and Dwight over Dwight's accounts. Back at Dunder Mifflin, Jim pretends to confide in Andy.
The Michael Scott Paper Company is gaining clients by offering lower prices than Dunder Mifflin, but is going broke in the process. However, Dunder Mifflin is losing clients to him, and is desperate to buy him out.
Michael returns to Dunder Mifflin and brings Ryan and Pam in as salespeople, but the existing salespeople demand that Michael return the clients they stole back to them. Meanwhile, some employees take the idea of Casual Friday too far.
Michael regrets revealing that Stanley is having an affair, so he spreads a bunch of lies about everyone else to cover his tracks--except that one of the lies that he spread actually turns out to be true.
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 and Michael and Dwight meet twins.
10 years ago, Michael promised a group of 3rd graders he would pay for their college tuition if they graduated. Now comes time to pay, and he can't do it. At the office, Dwight's "Employee of the Month" idea gets Jim in big trouble.