March 20 and 21, 2017, be sure to tune in to see a two-part crossover musical treat starring Supergirl (Melissa Benoist) and Flash (Grant Gustin), with a special appearance from Benoist’s “Glee” co-star Darren Criss. The cast also includes Broadway musical veterans Jesse L. Martin (original cast of “Rent”), Victor Garber (“Godspell”), and Jeremy Jordan (“Newsies”).