JoJo no Kimyou na Bouken Part 4: Diamond wa Kudakenai

April 1999. Jotaro Kujo arrives to Morioh City in search of someone named Higashikata, and ends up running into a young man surrounded by delinquents. Jotaro then finds out that his name is Josuke Higashikata, and was exactly the person he was looking for.

Josuke spots the terrible and violent villain Angelo's Stand, and tells Jotaro about that incident. Jotaro figures it's a Stand that can somehow enter people, so he warns Josuke to not eat or drink anything until he can get to him. Right when he's told that, Josuke witnesses the Stand go into his mother, and then does the unthinkable.

Angelo's Stand ability was brought forth by the mysterious bow and arrow, and apparently they're also connected to Dio. After defeating Angelo, Jotaro thought that the danger had left the city, and tries to find the whereabouts of the bow and arrow. A few days later, Koichi is walking home with Josuke, and they pass a house that should be empty...

In order to save Koichi, Josuke goes further into the Nijimura household. Suddenly, he's attacked from many tiny beams of light. Josuke manages to dodge the attack, but it hits Okuyasu right in the face. Josuke tells Okuyasu that he'll heal his wounds if he tells him what the identity of his brother's Stand is. Okuyasu says he has no itention of telling him, and Josuke does something surprising...

Josuke and Koichi defeat Keicho. They go further into the Nijimura house, in order to destroy the bow and arrow to make sure there will be no more victims. However, they end up hearing strange noises in the dark room they happen upon. As soon as Josuke tries to jump into the room, a monster-like hand grabs Koichi's leg...

Riding his bike to school, Koichi accidentally runs over a bag that was in the road that had a cat inside. Koichi is instantly overwhelmed by what happend. Then suddenly, a man named Tamami Kobayashi appears. Despite it being an accident, he demands money from Koichi, saying that he'll use it to bury the cat. Koichi can't process what's going on, but Tamami keeps pushing that he can't just leave after what happened. Koichi is filled with guilt, and then suddenly, a giant lock pops out of his chest...

Josuke and Koichi hear from Tamami that a high school student named Hazamada might also be a Stand user, so the two go to the school and investigate. Josuke checks inside Hazamada's locker, and finds a strange wooden doll inside, but nothing else out of the ordinary. However, as Josuke is inspecting the doll, it suddenly turns into Josuke, and attacks him and Koichi...

Koichi is asked out by another student in his grade named Yukako Yamagishi. At first, he couldn't hide his joy from being asked out, but quickly has second thoughts when she suddenly loses her temper with him. The next day, she knitted him a sweater, made him lunch, and did other things for him that makes Koichi start to wonder about her. Yukako obssession worsens, and she does the unthinkable.

Koichi can't handle living in captivity any longer and tries to plan his escape. While talking to Yukako, Koichi finds out that there's a payphone nearby, and has Echoes go find it. He tries to contact Josuke and Okuyasu, but Yukako already figured out what he was planning. Koichi loses hope. Yukako then goes to the phone to order some ingredients but then something unexpected happens...

Josuke and Okuyasu visit a brand new Italian restaurant in Morioh. Rather than customers choosing items from a menu, the chef, Tonio, decides what the customer will eat after he looks at them. Tonio wants Okuyasu to feel better, and first, offers him water. Okuyasu is moved at how wonderful it tastes. He's actually moved to tears at how delicious the water is, but then starts showing even weirder symptoms...

Red Hot Chili Pepper shows himself in front of Josuke. He seems to be more powerful than Jotaro, and is able to travel anywhere where electricity flows. Jotaro summons Josuke, Okuyasu, and Koichi and tells them that a certain someone is heading toward Morioh...

In order to defeat Red Hot Chili Pepper, who intends on killing Joseph Joestar, Josuke and the others head to the harbor. Jotaro believes that Red Hot Chili Pepper will try to get to Joseph's boat with something that requires a battery, so he leaves Josuke and Koichi at the harbor, telling them to attack the user if he shows himself. As Josuke is dealing with his conflicting feelings towards Joseph, the very confident user of Red Hot Chili Pepper shows himself.

Josuke and the others successfully capture Akira Otoishi and safely retrieve the bow and arrow. Peace is back in Morioh, but Josuke still faces a big problem... He still can't seem to get closer to his father he just met, Joseph. He agrees to let Joseph look upon his mother from a distance and they head toward his house, but Joseph accidentally gets onto the wrong bus. He manages to catch up to Joseph, but then Joseph tells him that there's a Stand user nearby...

Koichi and Hazamada find out that the famous comic artist, Rohan Kishibe, who draws "Pink Dark Boy," lives in Morioh and they go to his house to get an autograph. Not only did Rohan promise them autographs, but invited them inside to see his work space, and the boys are thrilled. Though Koichi gradually becomes frightened when he sees just how far Rohan will go to achieve reality...

Koichi suddenly arrives at Rohan's house. Koichi carefully goes inside and finds Rohan drawing manga at an incredible speed. Apparently he can't stop himself from drawing after reading about Koichi's experiences. Rohan attempts to tear another page from Koichi by using Heaven's Door, when someone unexpected shows up at his door...

Josuke suddenly gets invited to go hunting by Jotaro. The purpose of this hunting trip was to hunt down the rat that gained Stand abilities after Akira Otoishi shot it with the bow and arrow. As they trace the rat to a drainage canal, they see a clump of fourteen rat corpses fused together. They realize it's probably the work of the rat that they're after and follow it to a farm, and...

Koichi and Rohan discover a bizarre sight. Before them lies an alley that's not listed on any map. They decide to go down the alley and find only empty houses that are also not listed on the map. While wandering they realize that no matter which way they turn, they keep ending back where they started. Rohan believes that they're under a Stand's attack, but...

As Josuke was worrying about not having any money, a tiny little Stand holding a 1-yen coin appeared in front of him. A surprised Josuke follows it and encounters a new Stand user name Shigekiyo Yangyu (Shigechi)! Josuke is moved by the fact that Shigechi uses his Stand, Harvest, to pick up all of the forgotten coins around the town and figures out an even better idea using Harvest...

Josuke and the others head to the bank with their lottery ticket, but the bank is suspicious if that ticket really belongs to them. Josuke insists that they bought the ticket, but they find out that someone else's name and phone number are written on the back of the ticket, and the bank clerk decides to call the number. Seeing that they can't get out of this situation, Josuke takes action...

Yukako, who was depressed because Koichi wouldn't look her way, sees a mysterious shop one day called Salon Cinderella. Unlike other salons, apparently this was a salon that created faces to bring people fortune. The esthetician, Aya Tsuji, gives Yukako a face that allows her to encounter love. Yukako goes out and immediately runs into Koichi, and he seems different than usual. Yukako had never felt happier in her life, but the effects only lasted 30 minutes...

As Yoshikage walked through the town at lunchtime, declined the offer to eat lunch with his female coworkers, and heads to a bakery to buy lunch. While enjoying his lunch outdoors, Shigechi walks by and accidentally takes Kira's sandwich bag by mistake, thinking it was his own. Realizing this, Kira quickly goes after Shigechi, because the contents of that bag definitely did not contain a sandwich...

Yoshikage Kira was the killer hiding in Morioh and is also a Stand user. Shigechi finds out this secret, so Kira tries to dispose of him, but Shigechi fights back with Harvest. However, because of Kira's Stand, Killer Queen, he suffers a mortal wound and loses. Shigechi manages to get away from Kira and tries to find Josuke so he can tell him about Kira and be fixed by Crazy Diamond.

Jotaro and Koichi try to track down the owner of the button and run into the murderer, Yoshikage Kira and his Stand, Killer Queen's bomb, Heart Attack at Centipede Shoes. Koichi wants to go after Kira, but Jotaro tells him not to. However, Koichi isn't satisfied with Jotaro's decision and decides to act on his own, right when Sheer Heart Attack attacks again...

Koichi manages to survive because Echoes Act 3 made Sheer Heart Attack heavy, but then the murderer, Yoshikage Kira shows up! Feeling intense anger against the murderer, Koichi fights Kira with Act 3, but doesn't stand a chance. Kira is infuriated by the fact that Koichi made a fool of him in public, and lets loose on him, but...

Josuke and the others head to the house that Yoshikage Kira used to live to try to find some clues on him. Kira had very few unique characteristics, but Jotaro comes to the conclusion that he hid all of his potential on purpose so he wouldn't stand out. They also find jars of nail clippings as well as their data in the room. Josuke is rather creeped out by this. Suddenly, the hear the Polaroid camera on the desk suddenly take a picture...