Sugimoto Saichi, called "Immortal Saichi" for his incredible powers of survival, is panning for gold in the far north when he hears a story about buried treasure, hidden by a death row inmate. He decides to go after the treasure, but it will be a journey far longer and far more dangerous than he'd ever imagined...

Saichi and Asirpa head to Otaru, the largest town in the area, in seach of the tattooed prisoners. They quickly find out that they're not the only ones after the treasure. The army is looking for it too! Saichi has to face off against a deadly sniper, and a horrible cold front is setting in too...

Sugimoto and Asirpa are pursued by soldiers from the 7th Division. Private Genjirō Tanigaki finds Asirpa, but is fought off by Retar. Sugimoto evades capture after diving into a bear cave, whose occupant charges and kills the soldiers before succumbing to its wounds. Sugimoto and Asirpa take a baby bear found in the cave to Asirpa's village, and visit Asirpa's grandmother ("Huci"). Lieutenant Tokushirou Tsurumi, the leader of the 7th, mounts a search effort for the missing soldiers. Meanwhile, at a brothel in Otaru, Hijikata ambushes the tattooed prisoner Ushiyama Tatsuma, and offers to work with to him collect the tattooed skins.

Sugimoto leaves the village and returns to Otaru alone, where he learns of the incident with Ushiyama. He is captured by Tsurumi, who accuses him of killing the soldiers. Asirpa and Retar track Sugimoto and find Shiraishi, who tells her Sugimoto's location.

Sugimoto is tortured by twin brothers Youhei and Kouhei Nikaidō. Shiraishi breaks into Sugimoto's cell and releases his bonds, allowing him to kill Youhei. He fakes a fatal injury using Youhei's intestines, and is able to escape and reunite with Asirpa. While hunting, Asirpa and Sugimoto come across the tracks of two men: Tanigaki and Tetsuzō Nihei, a famous bear hunter.

Nihei tells Tanigaki that he wishes to hunt Retar, the last Hokkaido wolf. Asirpa and Sugimoto are joined by Shiraishi, who tells Asirpa and Sugimoto that Nihei is a tattooed prisoner. Asirpa, Sugimoto and Shiraishi track the hunters and ambush them.

Sugimoto and Shiraishi fight Nihei, while Tanigaki captures Asirpa. Tanigaki is shot by a poisoned arrow after stepping in a deer trap, but is saved by Asirpa. Retar rushes to Asirpa's aid with his mate, a grey wolf, who attacks and kills Nihei. Tanigaki is brought to Asirpa’s village to recover, and tells them that Tsurumi intends to use the gold to mount a military coup to form an independent Hokkaido. At a brothel, Ushiyama finds Shiraishi and gives chase.

Caught by Ushiyama, Shiraishi is pressured by Hijikata into acting as his mole in Sugimoto’s group. Sugimoto, Asirpa, and Shiraishi hear rumors of Henmi Kazuo, a tattooed prisoner who is also a psychopathic killer. They go whaling and unknowingly rescue Henmi after he falls into the water. Henmi conceals his tattoo, but vows to either kill Sugimoto or die in the attempt.

Hemni and Sugimoto are confronted by 7th Division soldiers. As they flee, Hemni attempts to kill Sugimoto, and they engage in a violent struggle before Sugimoto fatally stabs him. An orca beaches and grabs Hemni’s body, though Sugimoto, Shiraishi and Asirpa are able to recover it. Meanwhile, Ogata and Nikaidō find Tanigaki at the Ainu village, and accuse him of killing his companions and deserting the 7th. Tanigaki realizes that are battling factions within the 7th, and prepares to defend himself.

Tanigaki, a Matagi, escapes his pursuers by using his skills in hunting and trapping. Tsurumi arrives, and forces Nikaidō to expose the traitors in the 7th after cutting off Nikaidō’s ear, though Ogata evades capture. Elsewhere, Shiraishi is grabbed by a massive huchen after falling in a river, but is saved by Kiroranke, a former friend of Asirpa’s father. Kiroranke reveals that Asirpa's father is Nopperabo, and that he is now in Abashiri Prison. They begin to travel towards Abashiri to confront Nopperabo.

The group and Ushiyama separately check into a hotel run by Ienaga Kano, a tattooed prisoner who murders and eats her guests. Shiraishi and Ushiyama are held in a basement torture chamber while Ienaga attempts to kill Asirpa, but is thwarted by Sugimoto. A series of events triggers an explosion that destroys the hotel, burying Ushiyama and Ienaga in the rubble. Sugimoto's group continue on to Abashiri Prison.

Shiraishi meets Ushiyama and Ienaga, who survived the explosion, but does not disclose this to Sugimoto. Sugimoto’s group encounter Inkarmat, a traveling Ainu fortune teller who Asirpa does not trust. Shiraishi takes Inkarmat to a horse race, where they win two races on Inkarmat’s predictions. Kiroranke meets old friends at the track, who ask him to ride a horse and throw the race at the behest of a yakuza boss. Shiraishi bets all his money on the last race, but it is won by Kiroranke, who defies the yakuza boss. In Barato, Ogata meets with Hijikata and joins his group.

While searching for the body of a tattooed prisoner stolen from his grave, Tsurumi encounters Edogai Yasaku, a taxidermist who creates clothing from human skin. Tsurumi wins Edogai's affections by praising his skills, and commissions Edogai to create fake tattooed skins to confuse the other treasure hunters. At Asirpa's village, a recovered Tanigaki promises Huci that he will bring Asirpa home safely. He is joined by Inkarmat, unaware that she is working for Tsurumi.

Sugimoto and Shiraishi track Hajime Tsukishima, a sergeant in the 7th, back to Edogai's workshop, and find it under attack by Ogata. Edogai flees into a mine, where he is caught in a series of explosions; he dies, but is able to relay to Tsukishima how to distinguish the fake skins. Hijikata and Sugimoto's groups meet, and reluctantly agree to cease hostilities now that Tsurumi possesses fake tattooed skins.

The collected groups search Edogai's workshop for a way to identify the fake tattoos, but are attacked by the 7th. The groups split up, with plans to reunite in Ashibetsu. Elsewhere, Tanigaki and Inkarmat agree to travel with the orphan Cikapasi. Hijikata makes plans to break into Abashiri Prison to question Nopperabo, utilizing Shiraishi's escape skills. After a dream where Sugimoto kills him for his betrayal, Shiraishi flees, but encounters the 7th.

Shiraishi is captured by the 7th, though Hijikata and Kiroranke attempt and fail to rescue him. Tsurumi meets his old friend Lt. General Arisaka, a weapon designer who gives Nikaidō a false leg that can fire buckshots. Hijikata introduces his companions to Kiyohiro Suzukawa, a con artist and tattooed prisoner. Suzukawa disguises himself as Shirosuke Inudō, the warden of Abashiri Prison, in an elaborate plan to rescue Shiraishi.

The disguised Suzukawa attempts to bribe the 7th for Shiraishi's freedom, but he is killed Second Lt. Koito Otonoshi, who foils the plot on Tsurumi's behalf. Sugimoto flees with Asirpa, Ogata, and Shiraishi on an experimental hydrogen airship, though they are pursued by Koito. The group manages to throw Koito off the ship and escape the 7th by travelling through the Daisetsuzan mountains.

Tanigaki receives a telegram informing him that Huci is near death. He reflects on his friendship with Kenkichi, a fellow Matagi who married and later murdered Tanigaki's sister; he vowed revenge, and joined the 7th after hearing a rumor that Kenkichi had joined the army. He later enountered a dying and blinded Kenkichi at the Battle of 203 Hill, who told Tanigaki that he euthanized his sister after she caught smallpox. In the present, Tanigaki's group finds Asirpa, Sugimoto, Ogata and Shiraishi.

Tanigaki informs Asirpa of Huci's failing health, though Asirpa wishes to continue the search for the gold. They are joined by Nihei's dog Ryu, who has followed the scent of his former master's gun, now carried by Tanigaki. Meanwhile, Tsurumi tells Koito the truth behind the death of Lt. General Kōjirō Hanazawa, former commander of the 7th. Hanazawa abandoned Ogata, his illegitimate son, rendering his mistress neurotic. Ogata poisoned his mother, killed his half-brother (Hanazawa's legitimate son) at the Battle of 203 Hill, and murdered his father, staging his death to resemble a ritual suicide in penance for the loss at 203 Hill. Tsurumi exploited Hanazawa's death to motivate the 7th against the Japanese government.

A locust swarm separates Asirpa and Inkarmat from the group, where Asirpa questions Inkarmat about her father. Inkarmat says that Asirpa's father is Wilk, a Polish-Ainu man with blue eyes who was killed by Kiroranke. Elsewhere, the men cook sea otter meat given to Inkarmat and Tanigaki, and become aroused from its aphrodisiac effects. Reunited, Kiroranke denies Inkarmat's accusation. Despite mounting distrust, the group agrees to continue on to Abashiri. In Abashiri, Inudō attempts to kill Usami, a new guard feeding information about Nopperabo to the 7th, but is unsuccessful.

At a village near Lake Kussharo, Sugimoto's group learn about a group of blind bandits led by a man with strange tattoos. Shiraishi identifies him as Toni Anji, an Abashiri prisoner. The group is attacked by the bandits while the men are bathing in an onsen, but are rescued by Hijikata and Ushiyama, who are seeking Anji's tattoo. Mid-escape, Inkarmat has a premonition the she will die after falling underwater, but is saved by Tanigaki. Meanwhile, Usami reports to Lt. Tsurumi that Inudō is stockpiling weapons.

Sugimoto's and Hijikata's groups secretly tunnel into Abashiri Prison and link up with Chief Kadokura, an associate of Hijikata's. On a moonless night, they launch the escape plan: Inkarmat, Cikapasi, Nagakura and Ienga wait behind; Ogata stands lookout; Kiroranke, Ushiyama and Hijikata stand by; and Sugimoto, Asirpa, Shiraishi, and Anji enter the prison. They find a substitute in Nopperabo's cell, who screams and raises the alarm. Amid the chaos, Tsurumi and 7th Division attack the prison from the river in warships, seeking both Nopperabo and Asirpa.

Under the guise of quelling a prison riot, Tsurumi leads an assault on Abashiri Prison. Tsurumi corners Sugimoto in Nopperabo's cell, but Kadokura releases the master prison lock to save himself, freeing all of the prison's inmates. Hijikata and Anji take Asirpa and follow Inudou to a chapel where Wilk is being held, but Asirpa flees. Sugimoto escapes, but is badly wounded by Nikaidō. As Sugimoto drags himself away, he encounters a crippled man with blue eyes.

The blue-eyed man confirms he is Wilk after seeing Asirpa's makiri[b], but says he will only reveal the location of the gold to Asirpa. Wilk tells Sugimoto that he wished to raise Asirpa to be the guerrilla leader of the Ainu, and that he did not kill the Ainu to acquire the gold. Sugimoto and Wilk are suddenly shot in the head by Ogata, killing Wilk. Tanigaki pulls them out of the line of fire, but finds Inkarmat stabbed, who warns him that Kiroranke has betrayed them. Shiraishi flees with Asirpa, where they are joined by Kiroranke and Ogata, who tells them that Wilk and Sugimoto are both dead. Sugimoto awakens heavily bandaged, while Inkarmat recovers nearby, watched by Tsurumi. Assuming that Kiroranke is taking Asirpa to his associates in Karafuto, Tsurumi sends Tsukishima and Koito with Sugimoto and Tanigaki to intercept them. Asirpa has a dream in which Sugimoto tells her that he is still alive.