Once Upon a Mattress

In this 2005 made-for-television musical comedy film, Queen Aggravain has ruled that none may marry until her son, Prince Dauntless, marries. However, she's managed to sabotage every princess that comes along. When Sir Harry and Lady Larken learn they're going to be parents, he goes off to the swamps and brings back Princess Winnifred ("Fred" to her friends), who is a princess from the northern swamps. As the story unfolds, the kingdom prepares for a ball where Aggravain plans to exhaust Winnifred with a grueling dance to ensure she fails the test, but Winnifred's sensitivity and kindness win over Dauntless and the kingdom staff, ultimately leading to her surprising success in passing the test.