"Green Day" and "Oasis" (『グリーン・ディ』と『オアシス』 "Gurīn Dei" to "Oashisu") is the twenty-first story arc in Vento Aureo.
It narrates Bucciarati's Gang's arduous attempt to escape the duo of Passione Stand User Cioccolata and Secco, and the simultaneous battles between Giorno and Mista against Cioccolata and Bruno against Secco.
In the road to Rome, the gang realizes that Cioccolata's Green Day has spread its mold into Rome and they are forced to get out of the car. Seeing that Cioccolata is operating from an helicopter and Secco diving into the streets to fight them head on, Giorno and Mista immobilize the helicopter at the top of a tower, and go confront the mad doctor while Bruno takes care of Secco.
At the top of the tower, Cioccolata almost kills Mista. Giorno then manage to kill Cioccolata after a long clash. However Cioccolata heard that the gang is headed toward the Coliseum to get an unstoppable power, and has informed Secco upon his death.
In the streets, Bruno is physically bested by Secco. The fights transforms into a race toward the Coliseum, the third party being eventually revealed to be Jean Pierre Polnareff. When Bruno deafens Secco, crippling his fighting ability, Secco is forced to take an unwitting Doppio hostage. Bruno promptly defeats and kills Secco.
Not knowing who Doppio is, Bruno tells him that he's headed to the Coliseum, peaking Doppio's interest.