Die sechs Schwäne (2012)

On her 18th birthday, Constanze encounters a highly guarded secret. She discovers in amazement that she has six brothers, who have been transformed into snow-white swans by a careless word from their father on the day of Constanze's birth. Constanze is stunned when suddenly the six swans appear. They explain to her sister that only she alone can curse the curse: for six years Constanze could not speak a single word and has to sew shirts made of stinging nettles. The shirts will be able to turn the swans back into people.

Unfortunately the movie Die sechs Schwäne is not yet available on HBO Max.