Diamond is Unbreakable - Chapter 21 
Koichi Hirose (Echoes), Part 3 (広瀬康一(エコーズ) その③ Hirose Kōichi (Ekōzu) Sono 3), originally Atlantic Heights (アトランティック・ハイツ Atorantikku Haitsu) in the WSJ release, is the twenty-first chapter of Diamond is Unbreakable and the two hundred eighty-sixth chapter of the JoJo's Bizarre Adventure manga.
Around 4:07 PM, Koichi comes back home, lightly kicking his dog Police lying on the porch to check if he's still alive. Walking in, he spots unfamiliar shoes and hears someone talking with his mother in the living room. When he checks to see who the visitor is, he sees with shock that it is Tamami, who is massaging his mother's shoulder while chatting with her.
Koichi screams at Tamami, asking him why he is in his house. Koichi is presented with the 7,000 yen stolen from him, which Tamami is now pretending to return. He claims that when Koichi bumped into him with his bicycle, they accidentally exchanged wallets and that his contained over 500,000 yen. Tamami adds weight to his accusation by commenting that the wallet in Koichi's possession contains a bill from a dinner he had the night before, and to Koichi and his mother's surprise, the bill is indeed in the wallet.
Tamami asks Koichi's mother if she feels guilty for raising such a trouble-making son, and despite Koichi's protest, The Lock appears on her chest, throwing him into a panic. He tries to hit Tamami, but misses; Tamami tells him that he won't be satisfied with 500,000 yen alone and may also take the house's mortgage, pushing Koichi to try to call Josuke. Tamami doesn't let him, however, and Koichi's older sister Ayana appears with The Lock already on her heart as well. Tamami explains that she spilled some tea over him earlier, enabling him to exploit her guilt, and states that he considers sexually taking advantage of her as well. This enrages Koichi, who promptly pushes his mother and sister out of the room, shutting the door on their way out. In anger, Koichi summons his Stand, which hatches from its egg.