Barney bases a holiday on a near miss pregnancy, is followed around by a bunch of silent morons. Lily and Marshall contemplate a baby. Ted and Robin have nothing to do so they argue the entire episode.
Barney has the tables turned on him when he decides to court Quinn/Karma and gets gaslighted and his pockets emptied. Robin becomes more captor than guest while staying with Marshall and Lily in Long Island.
In a clever ruse, Barney and Quinn set up the gang to believe they've ruined their relationship. Robin and Ted squable over Quinns apartment and Marshall retells ill advised sex stories about him and Lily.
While Marshall and Lily struggle to find an affordable Nanny, Barney grabs their best option from under their noses and Ted/Robin compete over who has the best relationship.