"BROTHER AND SISTER" is a fairy tale about a young boy and his sister who escape their cruel stepmother, only for the stepmother, who is a witch, to bewitch all the forest's brooks. The siblings encounter these brooks on their journey, with each one warning that drinking its water will turn the drinker into a different animal. The sister saves the brother from turning into a tiger and a wolf, but cannot prevent him from drinking from the third brook, turning him into a roebuck.
Living deep in the forest, they lead a peaceful life until a king's hunting party arrives. The roebuck yearns to join the hunt, and the sister allows it, setting a password for his return. Eventually, the king discovers their cottage, meets the sister, and proposes marriage. The sister agrees, ensuring that her roebuck brother accompanies them to the palace.
Meanwhile, their wicked stepmother, who had assumed they were dead, discovers they are alive and well. Consumed by envy, she and her ugly one-eyed daughter devise a plan to dethrone the sister, which results in the queen's death and her own daughter posing as the queen. However, the real queen's spirit visits her newborn child and the roebuck at midnight. After the nurse tells the king about these visits, he keeps watch, and at the queen's third visit, she comes back to life. The stepmother and her daughter's evil deeds are exposed. The stepmother is burnt at the stake, the daughter is killed by wild beasts, and the brother, released from his curse, becomes human again, ensuring a happy ending for the brother and sister.