Lost in a perilous forest, a widowed king can only escape by agreeing to wed a witch's daughter. His new queen, Greta, resents the attention he gives his children and plots revenge, secretly changing his six sons into swans one night. Only his daughter, Elisa, is left untouched. Setting out alone, the princess searches far and wide until she finds her brothers sheltering in a distant cave. Seeing how badly the curse has harmed them, she vows to restore them to human form whatever it costs. Drawn from Andersen's The Wild Swans and the Grimm tale The Six Swans, this 1977 fantasy film leans toward action and gives its characters more depth than usual.