Barney goes back to his womanizing ways to get over his recent breakup with Quinn, organizing a festival called "Bangtoberfest" to pick up women, but it flops. Barney is forced to try other gimmicks such as adding children's toys to his apartment and try to seduce young women under the guise of a widower seeking a nanny for his child. It backfires as well when all the women he seduced at the apartment (all of whom have become nannies) corner Barney on the street and beat him up.
With Marshall and Lily's parental leave about to expire, the two scramble to find a nanny to take care of baby Marvin. After fruitless searches over a nanny agency's website (which Barney used for his own plays), an elderly British woman named Mrs. Buckminster quickly emerges as the leading candidate, until they realize that they cannot afford her salary demands. The second favorite nanny who comes from the same village as Marshall seems like a perfect match, but after her last interview of the day tells them that she won't be becoming a nanny because she met a rich man. Lily and Marshall immediately realize it was Barney.