Doraemon's Adventures of The Black Cauldron is an upcoming film. It will appear in a near future.
In the land of Prydain, Taran (Grant Bardsley) is an "assistant pig-keeper" on the small farm of Caer Dallben, home of Dallben the Enchanter (Freddie Jones). Dallben learns that the Horned King (John Hurt) is searching for a mystical relic known as the Black Cauldron, which is capable of creating an invincible army of undead warriors, the “Cauldron Born”. Dallben fears the Horned King may try to steal his pig Hen Wen, which has oracular powers, and use her to locate the cauldron. Dallben directs Taran to take Hen Wen to safety; unfortunately, Taran's negligence and daydreaming cause Hen Wen to be captured by the Horned King's forces.
Taran follows them to the Horned King's stronghold. Along the way, he encounters the small, pestering companion Gurgi (John Byner) who joins Taran on his search. Taran leaves Gurgi to sneak into the castle and rescues Hen Wen, who flees, but all too soon he is captured himself and thrown into the dungeon. A fellow captive named Princess Eilonwy (Susan Sheridan) frees Taran as she is trying to make her own escape. In the catacombs beneath the castle, Taran and Eilonwy discover the ancient burial chamber of a king, where he arms himself with the king's sword. It contains magic that allows him to effectively fight the Horned King's minions and so to fulfill his dream of heroism. Along with a third captive, the comical, middle-aged bard Fflewddur Fflam (Nigel Hawthorne) they escape the castle and are soon reunited with Gurgi. When the Horned King realizes that Taran has escaped, he enlists his sidekick Creeper (Phil Fondacaro) to send the Gwythaints to track Taran down.
Following Hen Wen's trail, the four stumble into the underground kingdom of the Fair Folk—a group of small fairy-like beings who reveal that Hen Wen is under their protection. When the cheerful, elderly King Eiddileg (Arthur Malet) reveals that he knows where the cauldron is, Taran resolves to go destroy it himself. Eilonwy, Fflewddur, and Gurgi agree to join him and Eiddileg's obnoxious right-hand man Doli (John Byner) is assigned to lead them to the Marshes of Morva while the Fair Folk agree to escort Hen Wen safely back to Caer Dallben. At the marshes they learn that the cauldron is held by three witches—the grasping Orddu (Eda Reiss Merin), who acts as leader; the greedy Orgoch (Billie Hayes), who has a penchant for food; and the more benevolent Orwen (Adele Malis-Morey), who falls in love with Fflewddur at first sight: they cause a frighting Doli to abandon the group. Orddu agrees to trade the cauldron for Taran's sword, and he agrees, although he knows that to yield it will cost his chance for heroism. Before vanishing, Orddu, Orwen, and Orgoch reveal that the cauldron remains indestructible, and that its power can only be broken by someone who climbs in under his own free will, which is likely to kill him. Neither one of the companions will be able to do that, so it seems that Taran has traded his sword for nothing. Although Taran feels foolish for aspiring to destroy the cauldron by himself, his companions show their belief in him, and it appears that Eilonwy and Taran will kiss. Suddenly, the glorious reverie is broken when the Horned King's soldiers interrupt, having finally reached the marshes themselves. They seize the cauldron and everyone but Gurgi, and take their prisoners back to the Horned King's castle. Inside, the Horned King uses the cauldron to raise the dead and his Cauldron-born army begins to pour out into the world.
Gurgi manages to free the captives and Taran decides to cast himself into the cauldron, but Gurgi stops him and jumps into the cauldron himself. The undead army collapses. When the Horned King spots Taran at large, he infers the turn of events and threatens to throw the youth toward the cauldron; however, the cauldron's magic is out of control. It consumes the Horned King in a tunnel of fire and blood, as well as destroying the castle, using up all its powers forever. The three witches come to recover the now-inert Black Cauldron. However, Taran has finally realized Gurgi's true friendship, and he persuades them to revive the wild thing in exchange for the cauldron, forcing him to give up his magical sword permanently. Fflewddur challenges the reluctant witches to demonstrate their powers by the revival, and upon hearing Fflewddur's remarks, the witches decide to honor the request, restoring Gurgi to life. The four friends then journey back to Caer Dallben where Dallben and Doli watch them in a vision created by Hen Wen, and Dallben finally praises Taran for his heroism despite the fact that he prefers to be a Pig Boy.