EW has some new info and a picture from the upcoming Flash/Supergirl musical. The episode will include covers of Moon River (by Melissa Benoist) and Put a Little Love in Your Heart, along with other songs and some original works. They've also revealed that in the musical dreamland, Martin Stein, Joe West, and Malcolm Merlyn will be rival mob bosses. Winn will be a pianist in a club and Cisco will be a busboy who aspires to be an artist. They're also apparently hoping for a sequel, though it depends on the success of this episode.