Synopsis
In 1600, the swordsman Miyamoto Musashi is requested by General Marume Nagayoshi to aid the imminent battle at Sekigahara, between the armies of the Tokugawa and Totoyomi clans. The night before the battle, Miyamoto is assigned to assassinate a traitor within the Tokugawa clan's army, with the help of fellow soldier Majima Gorohachi. After carrying out the task, Miyamoto learns that his target was actually Yūki Hideyasu, the heir to the Tokugawa clan. Both Miyamoto and Majima escape, and later reunite with Marume, though he betrays them. Both men are also attacked by a platoon of soldiers led by Sasaki Kojirō, who bests them in combat. Nevertheless, the pair manage to escape Sasaki and Marume.
Many days later, Miyamoto and Majima are attacked once more by Tokugawa soldiers, but Majima seemingly sacrifices himself to allow Miyamoto to escape. Miyamoto takes Majima's sword to his village, and meets with his adopted sister, Ukiyo. The former learns that Majima was not Ukiyo's brother, but rather the murderer of her father, but Majima had took up the duty of protecting Ukiyo and her village as penance for his sin. Miyamoto decides to give up his old life and stay with Ukiyo. A year later, bounty hunters arrive at the village looking for Majima, but recognize Miyamoto and fight him. Despite his efforts, Miyamoto is unable to prevent the hunters from fatally wounding Ukiyo. Miyamoto leaves behind one of his swords at Ukiyo's grave, then leaves the village. He fends off more bounty hunters until he is rescued by a wandering monk, who points him toward the Gion district. At Gion, Miyamoto encounters a courtesan named Yoshino, who bears a striking resemblance to Ukiyo. He ends up becoming a bodyguard for the Tsuruya brothel after saving one of the courtesans. The monk gives Miyamoto a new name: Kiryu Kazumanosuke.
In 1605, Kiryu is approached by a young girl named Haruka, who asks him to kill "Miyamoto Musashi", who allegedly murdered her parents. Kiryu initially declines, then later agrees to take the job when Haruka sells herself to Tsuruya and becomes a courtesan. Kiryu meets with the information broker Hon'ami Kōetsu, who tasks him with recovering a golden statue from a gang of thieves led by Shishido Baiken. To his surprise, Kiryu discovers that Shishido is actually Majima, who has become amnesiac following his sacrifice to save Miyamoto five years ago. After defeating Majima in combat, Kiryu acquires the statue for Kōetsu. Kōetsu reveals to Kiryu that he knew of the latter's identity, but decided to respect his wish and not expose him. He also reveals that a swordsman bearing the name "Miyamoto Musashi" has been wandering around various dojos for five years issuing them challenges. Kiryu follows up on Kōetsu's information and goes to the Yoshioka Dojo, "Miyamoto"'s next target.
Kiryu bribes a Yoshioka student, Gion Toji, to gain access to their entrance exam. The dojo's masters, the Yoshioka brothers Seijuro and Denshichiro, argue over accepting Kiryu into the dojo, due to his status as a masterless samurai. Eventually, they decide to have him battle Seijuro. Kiryu emerges victorious and is accepted, but Toji reveals that he knows of Kiryu's true identity, having previously been a part of Marume's army, and that Kiryu must represent the dojo in fighting "Miyamoto". Kiryu trains with the Yoshioka Dojo for a month in preparation. He is later greeted by an old friend, Itō Ittōsai, who accuses him of being Miyamoto. Kiryu defeats Itō and confesses; the latter reveals that his family was killed ten years prior by Sasaki, and he wants to claim the right to kill him from Kiryu. Itō informs Kiryu that Sasaki will be in Gion in two days to attend a banquet, in celebration of the new Governor of Kyoto, Itakura Katsushige. The pair plot to kill Sasaki on the night of the banquet; Kiryu also learns from Kōetsu that Marume will attend the banquet.
On the night of the banquet, Sasaki arrives and kills the attendees at Tsuruya. Kiryu and Itō confront him, but before they could kill him, the brothel is set on fire. Kiryu seeks out Haruka, who had been tasked to serve Governor Itakura, and saves her, while Itakura is killed by Marume. Days later, Kiryu tries to speak to Haruka, but the latter refuses, revealing that she knew of his identity, and that her parents' murderer had a charm tied to their sword, similar to his. Kōetsu later informs Kiryu that "Miyamoto" is attending a tournament at Hozoin Temple, prompting him to sign up for the tournament. He finds out, however, that it was a ruse, set up by the temple's masters and Marume. Marume reveals to Kiryu that Itakura was sent to take Haruka back to the Tokugawa Bakufu, and that both Marume and Sasaki were tasked by the same master to kill her; though Marume could not commit the deed. Marume stresses to Kiryu that Haruka bears great importance, though he refuses to elaborate further.
On the day of "Miyamoto"'s duel with the Yoshioka Dojo, Kiryu meets with Seijuro, who accuses him of being a spy, and fights him. Kiryu is forced to kill Seijuro in defense, but he then learns that the challenge was fabricated by Toji and fellow Yoshioka student Ueda Ryohei, who seeked to usurp the Yoshioka brothers and take over the dojo. Itō arrives to fight Ueda, allowing Kiryu to find Toji before he could kill Denshichiro. Despite Toji's attempts to dissuade him, Kiryu fights and kill the former, then apologizes to Denshichiro for killing his brother. The next day, Kiryu meets with Ito and Kōetsu to discuss their next move. An old man who visits Kōetsu requests Kiryu to take him to Tsuruya to visit a relative. Upon returning to Tsuruya and meeting with Majima, the old man reveals to Kiryu that his relative was Haruka, and that he intends to buy her freedom from Tsuruya. Afterwards, Majima accidentally trips on a cobblestone and hits his head, recovering his memory in the process. Upon seeing Yoshino and mistaking her for Ukiyo, Majima deduces that Kiryu sold his sister to the brothel, and kidnaps Haruka. Kiryu learns of the kidnapping, and goes to Kiyomizu Temple to confront Majima. Yoshino stops them from fighting and reveals that she is Ukiyo's sister, Ageha, who sold herself to Tsuruya to give Ukiyo money.
Sasaki arrives at the temple, and reveals that Yoshino took his money to buy her own freedom, in exchange for setting Tsuruya on fire. He attempts to kill Haruka, but Majima stops him, though he is wounded and falls off a cliff afterwards. The old man arrives, prompting Sasaki to leave. The old man reveals to Kiryu and Haruka that he is the former shogun Tokugawa Ieyasu, and that he is also Haruka's grandfather. Her father, Yuki, was indeed murdered by Kiryu five years prior, under Marume's orders, who in turn took orders from the imperial liaison Nankobo Tenkai, as part of a plot to set up Ieyasu's third-born son, the easily manipulated Hidetaka, as the next shogun. Marume was ordered by Tenkai to also murder Haruka and her adoptive family afterwards, but he could not carry out the deed and let her escape. At the time, Marume carried a sword similar to Kiryu's, which caused Haruka to mistake Kiryu as the killer. Ieyasu offers Haruka to come back to Edo Castle with him, but she refuses, wishing to stay with Kiryu and Yoshino. Ieyasu tells Kiryu to travel to Yagyū village and find the legendary swordsman Yagyū Sekishusai, in order to learn more about those who plotted against him and Haruka. Kiryu spends the night with Yoshino, then travels to Yagyū, where he learns that Sekishusai was the wandering monk who helped him years ago. Sekishusai reveals to Kiryu that Sasaki is actually his son, who was blackmailed by Tenkai to do his bidding. Marume arrives at Yagyū and reveals that he also betrayed Tenkai years ago and has been helping the Tokugawa clan and Sekishusai to foil his plan. After begging for Kiryu's forgiveness, the two of them duel, with Kiryu emerging victorious.
Upon returning to Gion, Kiryu finds that Haruka has gone missing with no traces. One week later, during a celebration at Tsuruya of Yoshino's freedom and engagement to Kiryu, Sasaki arrives and informs Kiryu that he kidnapped Haruka and took her to Tenkai, who wishes to marry her to his puppet shogun, whom he intends to replace Hidetaka with. Kiryu bids farewell to his friends and embarks to Ganryū-jima, where he duels with Sasaki and defeats him. Tenkai appears and shoots Sasaki, boasting the imminent arrival of his army that would overthrow Hidetaka. A defiant Kiryu defeats Tenkai's men before facing Tenkai himself and rescuing Haruka. Hidetaka arrives at Ganryū, intending to kill Tenkai, but Kiryu stops him from doing so, suggesting that a trial be given to the traitor. However, as Tenkai's army approaches the island, a vengeful Sasaki kills Tenkai. Kiryu instructs Sasaki and Hidetaka to escape with Haruka in tow, while he stays behind to fend off the army. As the army disembarks, Kiryu charges at them, his fate ultimately left unknown.
Ten years later, in 1615, Sasaki, having gone back to using his birth name Yagyū Munemori, joins Marume in commanding Tokugawa's forces to fight the Toyotomi Clan during the Siege of Osaka. The men form a plot to rescue Hidetaka's daughter from enemy forces, with many volunteering to do it, having been inspired by the legend of Miyamoto Musashi. Elsewhere, a surviving Majima ponders whether Kiryu survived his fight with Tenkai's army.
