Adaptation of the first and second novel of "The Gormenghast Trilogy," "Titus Groan" and Gormenghast" by Mervyn Peake. Gormenghast is a crumbling castle, to which the 77th Earl Titus Groan is lord and heir.
The ancient family of Groan has been incarcerated for centuries in the vast crumbling castle of Gormenghast. But the dynasty is threatened by the charming and evil Steerpike determined to leave his menial position as kitchen-boy and achieve ultimate control of the House of Groan for himself. On the day that Titus Groan -- one day to be the 77th Earl of Gormenghast -- is born, Steerpike escapes the hellish kitchens. He finds himself in the bedroom of Titus' sister, Fuchsia, and charms her into letting him accompany her on a visit to Prunesquallor, the castle physician. Steerpike ingratiates himself into Prunesquallor's service and quickly becomes confidant to Titus' aunts Clarice and Cora. He plays on their vanity and greed, manipulating them into setting fire to the library of Lord Groan -- the 76th Earl -- during a family gathering.
Steerpike becomes a hero by stage-managing the rescue of the family from the burning library. Lord Groan is driven mad by the loss of his precious books. Warring servants Swelter and Flay conduct a fatal fight, resulting in the death of Swelter. Lord Groan, wandering in the Tower of Flints, releases the owls which inhabit the tower, and they peck him to death. Taunted by Steerpike, Flay offends Gertrude, Titus' mother, and is banised from the castle. Still only a toddler, Titus is declared the new Earl at a magnificent ceremony.
Steerpike bides his time, becoming an apprentice to Barquentine, the master of the ritual, in order to learn the castle's innermost secrets. He fakes the deaths of Clarice and Cora, sets about the seduction of Fuchsia and kills the Groan children's Nannie Slagg -- all to satiate his lust for power. Titus is educated by a series of eccentric professors, one of whom, Bellgrove, takes a special interest in the Earl's development. Titus resents the restraints of life at the castle, and particularly Steerpike, who embodies the rituals he so detests. Titus finds a secret passage, which leads him outside the castle walls for the first time in his life. There he meets Flay, now living in exile. Punished for his escapade, Titus' animosity towards Steerpike grows as he curses the rituals of Gormenghest.
Steerpike makes his first serious slip when he bungles the murder of Barquentine, leaving himself badly disfigured and dangerously ill. Nevertheless, he continues to run the castle affairs from his sick bed despite the growing suspicions of Prunsquallor and Gertrude. On his recovery, he resumes his seduction of Fuchsia. Meanwhile, Flay secretly returns to the castle to keep watch over Steerpike. He summons Titus and Prunesquallor to assist in his pursuit of Steerpike through the dark corridors. In a long-forgotten room, they find him gloating over the skeletons of Clarice and Cora, whom he left to starve to death. Realizing he has been discovered, Steerpike kills Flay and makes his escape.
Finally galvanized into action, Titus leads the castle inhabitants against Steerpike. Fuchsia refuses to hide Steerpike, but left in an emotional turmoil, commits suicide. As torrential rain floods the castle, the young Earl and the usurper fight a bloody duel to the death. Titus kills Steerpike. But, as the rain stops and the flood waters recede, Titus turns his back on duty and the empty rituals of the stones, leaving Gormenghast forever.