In April 1999, marine explorer Jotaro Kujo, who uses a physical manifestation of his psychological energy known as a Stand, travels to the Japanese town of Morioh where he meets two high school freshmen, Koichi Hirose and Josuke Higashikata. Josuke uses his Stand Crazy Diamond[d] to alter a target's atomic structure. Jotaro tells Josuke that he is the illegitimate son of Jotaro's grandfather Joseph Joestar and will receive some of Joseph's inheritance. After school, Josuke encounters a convenience store robbery and steps in after the robber insults his hair. Josuke discovers that the robber was being possessed by Aqua Necklace, a Stand used by the escaped killer "Angelo" Katagiri. Aqua Necklace escapes into the sewers while threatening to kill Josuke.