When Barney convinces the gang to help his mom move out of her home, they quickly learn that she has been very protective of Barney and lied to him about events throughout his life. Meanwhile, Ted gets upset when Robin oversells him to a blind date.

Lily and Marshall receive shocking news that has a profound impact on the gang. Ted begins his duties as best man for an old friend's wedding.

Barney concocts a plan when his father arrives at the hotel; Ted thinks he is being framed when a wedding-related duty gets messed up.

With only a half an hour left before the wedding, Robin and Barney panic; Lily and Marshall rewrite their wedding vows.