"Goemon's Revenge"note , with the English title "The Last Mastery". Released in 2003 by Geneon on Volume 4: Thieves' Paradise.
In the mountains of Japan, near the village of Iga, Goemon is traveling to see his ninja master, Jinen. While crossing over a river, he is nearly taken out by explosive darts. Realizing something is amiss, he hurries to his sensei's home, only to find his master dying, clutching half of a torn scroll. He bestows the ruined scroll on Goemon before he passes away...and an explosive planted in the house goes off. Wounded, but managing to escape, he vows revenge on the one responsible.
Meanwhile, in Hong Kong, Lupin, Jigen, and Fujiko are enjoying a dinner on a fancy boat and discussing their missing friend. Goemon's trip, his first back to his sensei in ten years, was to receive the final lesson of his training in the Iga Ninja arts. Fujiko also mentions a hidden Iga treasure, and Lupin brings up Jinkuro, another student of the Iga who is known for his competitive and relentless attitude. As the discussion ends, a barker pulls alongside in a small craft and tries to hock his wares, finally irritating Lupin enough for him to buy something. As Lupin hands him the money, the barker grabs Lupin's arm and attempts to attach handcuffs. Sure enough, Zenigata has once again found the master thief. Lupin distracts Zenigata with a couple of well-placed prawns, causing Zenigata to miss and cuff the railing of the boat instead. Lupin and his gang steal Zenigata's boat to escape, leaving the dangling detective.
Back in Japan, Goemon has taken refuge in a cave. Mourning his teacher, a vision of Jinen appears before him, comforting him and reminding him about the importance of spirit. As the vision fades, a taunting voice calls out for Goemon to come forth. Jinkuro has made his presence known. He tells Goemon he has framed the samurai for their teacher's murder. Furious, Goemon goes after his fellow student, and in the ensuing battle, is blinded by a bright light and has Zantetsuken snatched away. Jinkuro goes for the other half of the scroll in Goemon's possession, a map to the final lesson of the Iga Ninja. As he raises his sword to deliver the final blow, it is shattered by a well-aimed bullet from Jigen. Jinkuro flees, and Lupin and Jigen collect the wounded Goemon.
Hiding out in a farmhouse, Lupin inspects Goemon's half of the map. Jigen, arriving from a trip into town, tells Lupin that Zenigata has followed them to Iga, and that he and the local police have arrested Jinkuro for the murder of Jinen. Lupin speculates that Jinkuro is pleading guilty so that he can be kept in jail and safely out of the clutches of a vengeful Goemon, as well as creating a lure for leading Lupin's gang into Zenigata's clutches. Overhearing only the first part of the conversation, Goemon sneaks off to confront Jinkuro.
As Jinkuro is loaded into a police van, Goemon attacks. As speculated, the whole thing is a trap, and Goemon finds himself surrounded by riot police armed with gas grenades, who fire at Zenigata's order. Goemon is nearly subdued, choking on the smoke, when Lupin and Jigen drive out of nowhere, nearly taking out Zenigata with his car before grabbing Goemon and heading off. His plan failed, Jinkuro expresses his lack of confidence in Zenigata's skills, infuriating the detective.
Lupin's gang, meanwhile, have found a spot on a beachside cliff to cool down. Goemon is ready to go after Jinkuro again, but Jigen urges him to wait until Lupin can come up with a plan. After a round of fishing and a few other activities, Lupin leaps to his feet, ready to go.
At Jinkuro's trial, they announce that Jinkuro's confession to Jinen's murder is not enough to find him guilty alone. The prosecution begins submitting evidence, but it all turns out badly. The sword that is supposed to be the murder weapon turns out to be a flag with a sexy woman drawn on it, a picture of Jinkuro at the murder scene is a picture of the prosecutor partying drunk and naked, and the confession itself, which turns out to be a children's pop-up book. Furious, the judge declares the trial a farce and Jinkuro not guilty. Jinkuro rants as the judge leaves; meanwhile, under the docket is the real judge, bound and gagged. Lupin, taking off his mask outside the courtroom, leaves Jinkuro to Goemon.
That night, Jinkuro and Goemon (accompanied by his friends) meet for the final showdown, the two halves of the map laid out on a nearby rock. The two fight long and hard as a thunderstorm rages overhead. Finally, Jinkuro plays his secret move; he releases a numbing agent on Goemon from a hidden pack that Lupin and Jigen can't see. His vision blurred and cornered on a cliff, Goemon is finally trapped. Jinkuro, gloating, raises his blade for the final blow, but at the last second Goemon hurls Zantetsuken into the air; lightning strikes it and in turn directs the bolt to the sword in Jinkuro's hand. Bursting into flames, Jinkuro falls over, dead.
The next day, with the map pieced back together, Lupin locates the treasure hidden in an old tree stump. Resting inside is a small gold box with the last lesson. The box is opened, only to reveal a single scrap of paper scrawled with the worlds "Fortune favors cheerful homes." As Lupin and Jigen puzzle over it, Goemon comes to realize that the last and most important lesson is to enjoy life. Meanwhile, Jigen speculates on Fujiko's reaction to the "treasure", and the three enjoy a good laugh as Goemon finally bids his sensei goodbye.
This episode features examples of:
- Absurdly Sharp Blade: Goemon demonstrates on the fish Lupin catches.
- Adaptation Expansion: Most of this episode was originally taken from the manga. The victim was originally Goemon's uncle, not his ninja master, and the master's treasure was added, as was Goemon and Jinkuro's duel at the end. In the original, it was implied a fearful Jinkuro was killed by Goemon as soon as he was pushed out of the courtroom by the police no longer obligated to protect him.
- A Day in the Limelight: An episode for Goemon; in contrast, poor Fujiko gets pushed into one quick appearance towards the beginning.
- Arson, Murder, and Jaywalking: Jinkuro's rant at being found not guilty:Jinkuro: I'm as guilty as sin, I tell you! I killed him with my own hands! I'm a real bad guy!
- Chain Lightning: How Jinkuro meets his death, via a thrown Zantetsuken.
- Combat Pragmatist: Jinkuro, who's not above using and abusing explosive needles, knives, shurikens and even poison dusts and whips to give himself an advantage.
- Courtroom Antic: Lupin switching the real evidence for things that are far more goofy.
- Deceptive Disciple: Jinkuro.
- Enemy Mine: Zenigata and Jinkuro work together to trap Lupin and Goemon, even though Zenigata knows that Jinkuro is a Manipulative Bastard.
- Implausible Fencing Powers: Well, come on. It's a Goemon episode!
- Manipulative Bastard: Jinkuro. When he can't kill Goemon and take the secrets, he sides with Zenigata for protection via jail.
- Ninja: Goemon, apparently. This is the only time in the series that ever mentions he's had ninja as well as Samurai training. Jinkuro seems to incarnate the less honor-bound example, prone to compensate his fighting skills with tricks and deception.
- Roaring Rampage of Revenge: Goemon wants this, but Lupin manges to prevent him from getting too far and destroying himself.
- Ronin: Appears averted; however, Goemon has had several masters over the year and never declared his lifelong fidelity to any of them.
- Rummage Sale Reject: Jigen and Goemon's courtroom disguises are...interesting.
- Smoking Gun: Averted thrice, courtesy of Lupin's interference with the evidence.
- Spirit Advisor: Jinen to Goemon.
- Worthless Treasure Twist: The Iga treasure.