Tsuna is a failure at school, sports, and social life. He needs a mafia hit man mentor like he needs a hole in the head...and he's about to get both! Reborn's gun will kill you and make you stronger! Tsuna's old adversary, Mukuro Rokudo, has successfully fought on the side of Tsuna's "family" for possession of the Mist Ring. But his opponent, the Varia known as Mammon, has a highly developed sense of never-say-die! Later, Tsuna finally completes his training and returns in time to confront one of the Varia who is running amok. The whole game changes, however, when he finds out who this Varia really is!