Vivian holds auditions for a local stage play of ""The Sound of Music."" Delilah has her heart set on getting the part of Maria, but Bree makes ""Julie Andrews look like a two-bit lounge singer."" Meanwhile, Mother Buchanan agrees to play the role of the mother superior -- if she can sing ""Eidelweiss."" But Emma has her restraints about working with Hubert Lombard, who's playing the part of Captain Von Trapp. And when no one's around, Alex, who once sang ""Happy Birthday"" off key (and keeps being reminded of this), does some incredible vocal work of her own.