The gang is all at the bar, and they all still hate Karen. But more importantly, they all admit to Robin they've never watched her show. The gang agrees to have a pajama party at Marshall and Lily's, where they'll all stay up on Friday night and watch her 4:00 am show. Ted shows up to the party, mutes the television (thus missing her show, jerk!) and tells the gang that Karen dumped her. Apparently she found one of Robin's earrings in his bed and she thinks he's cheating on her and dumps him.
While at the house, Ted discovers Robin's other earring on Marshall's night stand and immediately accuses him until Lily admits it was her. Apparently Lily admits to sabotaging several of his relationships in a very A Few Good Men speech. Apparently Lily even broke up Ted and Robin by feeding them lines because she didn't want to lose Robin as a friend and they had separate goals. Lily explains she did it because those girls failed "The Porch Test," where she pictures how life will be when they're all old and hanging out on the porch playing Bridge (by their own horrible rules).
Feeling guilty about breaking up Ted and Laura, Lily sends Karen an apology letter and cooks a meal for them and sets it up in Ted's apartment. Ted and Karen meet at the bar and she wants to get back together if they never see Lily again. She hates his friends. Ted decides to dump her. He's okay she his friends hate his girlfriend, but he's not okay with her hating his friends. Ted invites Robin to share the homecook meal with him and they talk about their relationship. They agree to marry when they're forty if they haven't found anyone else.
Meanwhile, Marshall puts on a nightgown for his pajamas at the party. Barney initially puts on a silk suit (yeah, you'd have to see it to believe it) and makes fun of Marshall not looking good at all times. But soon, Barney also puts on a nightgown and decides maybe marriage, where you can be comfy and still get laid, may be the right path after all. Too bad he makes this discovery at a point when Robin and Ted seem to be rekindling.