"Duet" is the seventeenth episode of the third season of The CW television series, "The Flash", which aired on March 21, 2017, the  story begins at the end of the "Supergirl" episode ,"Star-Crossed" on March 20, 2017, which sees Kara Danvers / Supergirl (Benoist) being put in a coma by Music Meister, with who (Chris Wood), Lar Gand, and alternatively as Valor and M'Onel), is a fictional superhero appearing in American comic books published by DC Comics, commonly in association with the Legion of Super-Heroes, Superboy, and Superman, is primarily known as who?
Lar Gand Lar Gand, known primarily as Mon-El (and alternatively as Valor and M'Onel), is a fictional superhero appearing in American comic books published by DC Comics, commonly in association with the Legion of Super-Heroes, Superboy, and Superman. The character has been reinterpreted over the years, but in all versions, he serves as a hero with abilities similar to those of Superman, sometimes serving as a substitute for him.
Supergirl (TV series) Supergirl is an American superhero action-adventure television series developed by Ali Adler, Greg Berlanti and Andrew Kreisberg (the latter two having previously created "Arrow" and "The Flash") that originally aired on CBS and premiered on October 26, 2015. It is based on the DC Comics character Supergirl, created by Otto Binder and Al Plastino, and stars Melissa Benoist in the title role. Supergirl is a costumed superheroine who is Superman's cousin and one of the last surviving Kryptonians.