Elsa, Princess of Arendelle, possesses cryokinetic powers, with which she is able to produce or manipulate ice, frost and snow at will. One night while playing, she accidentally injures her younger sister, Princess Anna. Their shocked parents, the king and queen, seek help from the troll king, who heals Anna and removes her memories of Elsa's magic. The royal couple isolates the children in their castle until Elsa learns to control her powers. Afraid of hurting Anna again, Elsa spends most of her time alone in her room, refusing even to speak to Anna, and a rift develops between the sisters as they grow up. When the girls are teenagers, their parents die at sea during a storm.