''Shin Lupin III'': '''"The Wolf Saw an Angel"'''

Inspector Zenigata pulls up outside the Bank of Los Angeles, which is playing host to the world's largest exhibition of diamonds. Knowing the exhibit will be like catnip to Lupin III, Zenigata offers his services to the guards outside, but is interrupted by a bank robbery and a massive fire fight between the robbers and the local police. One of the guards informs the inspector that the bank has been the target of robbery attempts recently, up to six a day. Even with the police's impressive response, Zenigata is skeptical that they'll be able to tackle Lupin. Sure enough, as he speaks Lupin and Jigen are calmly and quietly tunneling underground to reach the vault in the bank's basement.

Back at the gang's hideout, Goemon asks Jigen to help him test his reflexes, feeling he is not wielding his sword efficiently. Jigen shoots down a number of steel beams, and Goemon manages to cut them all to bits, but he fails to note an apple fall from the same tree, which promptly bonks him on the head. Humiliated, he decides to journey into the California wilderness to strengthen his swordplay, which will in turn strengthen his heart. After dropping him off, Lupin and Jigen receive a phone call from Fujiko, who asks them how their caper is going before telling them she's going on a date with Harry Zettler. Jigen immediately recognizes the name as that of a legendary soldier and mercenary who disappeared years before. Fujiko said he also seeks the diamonds on display; if he's becoming involved in the scheme, it could become quite dangerous.

Going on the rumor that he's settled in nearby Mount Point, Lupin and Jigen investigate a ranch and the elderly farmer who lives there. At first, they suspect the bearded gentleman of being Zettler, but he fails to respond to any of their provocations, leading them to believe he's not the lost mercenary after all. Deciding the namedrop was another of Fujiko's tricks, the two decide to continue on their original plan.

Meanwhile, Goemon is sitting on a cliffside; a rattlesnake attempts to bite him, but he smoothly jumps away. However, his landing places him on a loose stone, causing him to slide down the cliff face and land near a gravestone at the bottom. Before he can find out more, a little girl singing a sweet tune, Mary, and her dog Joe come to visit the grave. Mary, who is blind, reveals that the grave is her mother's. What's more, she's blind, but her father tells her as soon as he saves up enough money, she can go into Los Angeles and have an operation to restore her sight. Feeling Goemon's long hair and robes, she mistakes him for the angel her mother said would bring happier times; not wanting to disappoint her, the samurai flees, causing a bird to fly from a nearby bush. One of its feathers lands across Mary's face, confirming her belief, and she and Joe happily run off in pursuit, with her calling for "her angel".

That night, as Mary goes to bed, she tells her father, the old bearded farmer, about the angel she met. Afterward, the farmer answers a phone call from Fujiko...he is Harry Zettler after all. Fujiko tells him Lupin will take the diamonds the next day, but the mercenary is not to harm the thief. On hearing Fujiko say she wants to split the loot 50/50, Zettler furiously smashes the phone. He trims off his beard, loads up his weapons, and transforms himself into the soldier he used to be.

Back at the bank, Zenigata is inspecting the vault and security measures when he realizes Lupin is under them as they speak, using acid to dissolve a hole in the floor of the vault. When he tries to capture Lupin in the tunnel, the thief manages to trap Zenigata with his own handcuffs before he and Jigen successfully enter. As the two thieves gleefully grab the gems, an explosion comes from the vault door; the heavily-armed Zettler has arrived to claim the diamonds to pay for Mary's operation. The mercenary chases the two thieves and their loot back through the tunnels; both make it to helicopters and fly out of the city, where Zettler is shot down by Lupin and Jigen. He returns the favor with a rocket launcher; the two begin to duel in an empty canyon. Zettler has prepared for this and has weapons such as bazookas and grenades stashed everywhere. He bombards the thieves with artillery, to the point Jigen and Lupin consider surrendering. Lupin manages to figure out where the last weapon is, but before he can go after it, Zettler fires a rocket at them, dead on target.

Suddenly, Goemon appears as if from heaven to save his friends, cutting the rocket smoothly in half and deflecting it from his allies. Zettler quickly realizes Goemon is the angel that Mary met. Swearing he will kill this "angel", he goes after his last weapon, a tank. Lupin has taken advantage of Goemon's distraction to reach it, however. Zettler attempts to throw a grenade at the thief, but in his desperation, he trips and fumbles it, and although he tries to toss it away, it isn't enough. Fujiko arrives just as Goemon, Lupin, and Jigen are look over the smoke from the explosion.

Filled in by the samurai, Lupin decides to give the diamonds to Mary to pay for her operation. Goemon waits inside, watching her as she's wheeled into surgery. He waits, and suddenly hears her voice counting to three; the operation has been a success. He realizes that he has been going about his training all wrong, and needs to find his heart to help his sword. And so he has Lupin and Jigen drop him off into the wilderness again...this time, he's the one looking for an angel.

!!This episode features examples of:
* BigDamnHeroes: Goemon, who arrives at the last second and saves his friends from an explosive rocket. The fact he appears as an angelic vision to the bad guy drives the point home.
* BishieSparkle: Goemon, when he appears before Harry. This is arguably Goemon's most {{Bishonen}} moment ever.
* BlindMistake: Mary mistakes Goemon for an angel because of his robes, thin face, and long hair.
* CouldntFindAPen: Not only does Goemon perfectly cut every beam into tiny pieces, but he makes the bits land so they spell out his name.
* {{Engrish}}: The sign at the ranch reads "Hally's Farm."
* ExpositoryHairstyleChange: Zettler shaves off his beard when he decides to go after Lupin and the diamonds for Mary.
* HatDamage: Zenigata is skeptical of the robbery claims until a bullet skims across the brim of the hat.
* LatexPerfection: Played with; Zenigata is constantly tugging on people's faces to make sure they're not Lupin in disguise. He is in turn on the receiving end of this from the bank president to make sure the detective's not Lupin...a wise precaution to take.
* LockAndLoadMontage: Zettler, before he confronts Lupin and Jigen.
* OfficialFanSubmittedContent: The fourth and final episode based on fan suggestions to celebrate ''Shin Lupin III'''s 100th episode.
* PowerGivesYouWings: Goemon, as he appears before Harry when he rescues Lupin and Jigen.
* ShootTheRope: A non-execution example that has Jigen shoot the ropes holding up the steel beams Goemon plans on cutting.
* TitleThemeDrop: As Lupin and Jigen drive to Zettler's ranch, "Lupin III '80" is heard, a tune that will become the new opening theme in the next episode.