King Alexander was happy with his commoner-born queen Marie, but all their three children are puppies (actually switched at the queen mother Eliza's orders by chamberlain Corbinian, who put each in a basket in the river), then she dies mysteriously. Twelve years later, the king still mourns, refusing to remarry any princess picked by his mother. Then on a hunting trip, he meets three kids who recall his late wife, Theo, Fritz and Lotte, foundlings raised by farmer Hans and his wife. Eliza decides to dispose of the princes terminally, by tricking them into attempting to seek infallible answers from the bird of truth, which requires two equally magical gifts, each likely to be transformed at failure into rocks.