The Youth Musical Theater Company in Berkeley will mount the popular musical, Once Upon a Mattress (February 20-28), a retelling of Hans Christian Anderson's "The Princess and the Pea." The show imagines a kingdom where no one may marry until Prince Dauntless is wed, and his future bride must first pass the queen's difficult test. The show features music by Mary Rodgers, lyrics by Marshall Barer, and a book by Jay Thompson, Dean Fuller, and Barer.