Todo parte en una de las misiones de uno de los subordinados del cuerpo de asesinato independiente Varia, cuando un par de sujetos llamativos acaba con un objetivo con el que tenía que acabar, desde ese punto el choque de ambas mafias mas grandes de Italia resulta ser inminente.

One shot! Tsuna, an up and coming mob boss has always been a bit… bizarre, from repeating the same words over and over, to releasing shrill battle cries, he's never really fit in, that is until a baby hitman comes into his life, introduces some friends and leads him to one Bizzare Adventure.

Tired of being weak, Sawada Tsunayoshi began to struggle against the limits placed on by others. When the young boy is given the chance to grow, he spreads his wings to see just far he'll go. Is the world ready for the new sky?

When the 10th Vongola Familia is sent to Naples to establish a treaty with the Passione, tragedy strikes. Join the two families as they travel together and fight a new foe.