Kurosawa takes on Shakespeare by reinterpreting Macbeth, transposing it to 16th-century feudal Japan and filtering it through the great cultural tradition of Nō theater. Throne of Blood has been described as the first example of an intercultural work of art in its interpolation of the English Renaissance and Nō theater. Indeed, long before all the actors appear on screen, the atmosphere of a Nō performance can be felt through the slow rhythm and high-pitched notes of Masaru Sato's music, which echoes the classic Nō musical accompaniment at the opening, while the credits are still rolling. The Nō form of masked musical drama was performed in Japan as early as the 14th century, and Kurosawa channels it more than evidently in this film while immersing the Scottish setting's scenery into a stylized world made up of warlike barons and warring demons. The result is an erudite and fascinating multitextual work, which never loses sight of the Shakespearean canon while simultaneously offering nine exciting interpretations of the playwright from Stratford-upon-Avon's work.

Although not explicitly stated, the Shakespearean partitioning of the original drama is evident in the plot. Therefore, in Throne of Blood, too, one can distinguish the 5 acts that characterize the narrative of Macbeth. In the First Act, generals Miki and Washizu are in the service of the local lord, Tsuzuki, who rules in the castle known as Spiderweb Castle, surrounded by defensive forts. After defeating the lord's enemies in battle, the two return to Tsuzuki's castle, summoned after the battle to receive homage from their sovereign. During their journey through the dense forest surrounding the castle, they encounter a spirit, who predicts their future. The spirit tells them that that day Washizu would be appointed Lord of the North Castle while Miki would become the Commander of Fort One. It then predicts that Washizu will eventually become the lord of Spiderweb Castle, and finally foretells that Miki's son would also one day become the lord of the castle. The two arrive at Tsuzuki's Castle deeply disturbed by the words of the forest spirit. Their lord rewards them with exactly what the spirit had predicted. While Washizu discusses this with Asaji, his wife, she ends up manipulating him into making the second part of the prophecy come true as soon as possible. This could only happen with the killing of Tsuzuki. In the Second Act, Washizu kills Tsuzuki with the help of his wife, who gives drugged sake to the lord's guards, putting them to sleep. When Washizu returns in shock after thrusting his spear into Tsuzuki in his sleep, Asaji grabs the bloody weapon and puts it into the hands of one of the three unconscious guards. She then screams "murder" throughout the courtyard, and Washizu kills the guard before he has a chance to defend his innocence. Tsuzuki's vengeful son Kunimaru and a counselor of Tsuzuki, Noriyasu, immediately suspect Washizu is the traitor and try to warn Miki, who refuses to believe that his best friend could be a despicable murderer. Washizu, however, is not fully certain of Miki's loyalty, but still chooses Miki's son as his heir, since he and Asaji have been unable to have a child. Washizu plans to announce his decision to Miki and his son during a large banquet, but Asaji reveals she is pregnant, which presents him with a dilemma regarding his heir, as Miki and his son must now be eliminated. And so begins the Third Act where, during the banquet, Washizu appears agitated, then the man breaks into furious shouts at the appearance of Miki's ghost (which Kurosawa never shows; only Mifune's gaze reflects the deep terror of that apparition while the camera is hypnotically fixed on his face). In his delirious panic, he reveals his treachery to everyone, exclaiming that he is willing to kill Miki a second time, going so far as to draw his sword and strike at nothing. Asaji attempts to downplay the situation and awkwardly dismisses the guests. Then one of his men arrives with Miki's severed head. The assassin reveals that Miki's son managed to escape the assassination, fleeing wounded. The Fourth Act opens with the tragic news of the death of Washizu's heir. The distraught man returns to the forest to summon the spirit. The spirit reveals to him that he will never be defeated unless the very trees of the forest around the Castle march towards him. Washizu laughs, deeming the event impossible. The following morning, Washizu is awakened by the shouts of the attendants. A panicked soldier screams that the trees of the forest "are advancing to attack us." The prophecy has come true, and Washizu is doomed. In the conclusive Fifth Act, Washizu tries to make his troops attack, but they remain motionless. Disappointed by his increasingly unstable behavior, the troops finally accuse Washizu of Tsuzuki's murder. In the final striking image (perhaps the most beautiful scene in the entire film), archers begin to unleash dozens of arrows towards Washizu, who struggles amidst a torrent of darts raining down from every side, hitting him and blocking his path. Struck dead, the samurai sees the forest trees reach the walls, revealing enemy soldiers who, camouflaged with bushes and foliage, had advanced to the very heart of the fortress.