The residents and interns treat the victims of a massive explosion at an apartment building; Mama Burke returns to collect her son's things; Lexie tries to have a heart-to-heart with unwilling Meredith.
With only a half an hour left before the wedding, Robin and Barney panic; Lily and Marshall rewrite their wedding vows.
Barney concocts a plan when his father (John Lithgow) arrives at the hotel; Ted thinks he is being framed when a wedding-related duty gets messed up.
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.
When the gang helps Barney's mother move, they learn that she has lied to him about events throughout his life; Robin oversells Ted to a blind date.