The Plant Appraiser - Rai Mamezuku (31) (story arc)

The Plant Appraiser (植物鑑定人) is the sixteenth arc of JoJolion.

Summary
Years ago, Jobin is shown as a shy and withdrawn child, whose Rock Disease was beginning to take root; therefore, he had cracks along his body and suffered memory loss. His mother Kaato meticulously reminds him of every one of his items' locations, also reminding him of a note in his backpack with more information. Later during the trip, the scout leader and one companion take Jobin far away from the group to bully him. They both violently hit him and forced Jobin to steal Kaato's underwear and bra earlier, and take a photo of her in the shower. Suddenly, another scout comes to check on Jobin, but the boy remains silent as the bullies falsely reassure the girl that nothing had happened.

Later, it is revealed that one of the bullies had been reported by the girl scout to the school and the police. The bully, desperate for his future, torments Jobin again. The bully then tries to force Jobin to sneak into the girl's house and set fire to it. This was too much for Jobin, who refuses to commit this crime. Furious, the bully douses Jobin with oil and threatens to light his face on fire with a lighter unless he obeys. At this moment, Jobin's Stand awakens. As Jobin grabs the bully's neck, Speed King boils the blood inside of it, causing a stroke.

Jobin goes back to his mother for help. Determined to save her son, Kaato takes the unconscious bully with her and puts him in her car and takes Jobin with her. She then drives with Jobin to the pine tree and the shrine and drags the still-disabled boy scout closer to the shrine. At this moment, Kaato tells her son that from now on, Jobin would "keep climbing" whereas others would be "left at the bottom". Finally, she instructs her son to take the bully with him inside the hole behind the shrine and bury him.

Since then, Jobin has been a healthy and outgoing teenager. However, the boy's corpse was eventually found and the investigation led to Kaato's incarceration in the autumn of that same year, which she served for 15 years for Jobin's sake.

In the present day, Josuke and Yasuho take a bus to go find the Plant Appraiser. Yasuho asks if leaving Dolomite alone is safe, but Josuke thinks that he won't be a nuisance anymore. However, he ponders on Dolomite's words about the Rokakaka. Dolomite had explained that in the grand schemes of things, Jobin is a simple gofer, and he himself only wishes to find his "Blue Lagoon" by healing himself with the fruit. Yet, another group is after the Rokakaka, a group that left Dolomite alive especially because he doesn't know anything about them and for whom the fruit is invaluable. Because Josuke is the result of a new variety of it, Dolomite advises him to back off from the chase for the fruit.

Josuke realizes that Dolomite had also been talking to someone else, who had been watching over them, hidden somewhere. Moreover, that same person must have overheard Josuke's destination. At this instant, the bus driver stands up from his seat and collapses on the floor. The plant appraiser who Josuke is supposed to meet makes his first appearance. Driving the bus, the plant appraiser asks for Josuke to protect him, as they are all now under attack.

Chapters

 * 064 (911). The Plant Appraiser, Part 1
 * 065 (912). The Plant Appraiser, Part 2