Truth of the Future is the 174th episode of the Katekyo Hitman Reborn! anime.
As Shoichi recovers from his injuries, he explains to Tsuna and the others about why he is obsessed with Byakuran. Using the Ten Year Bazooka ammo he had received from the Bovino Famiglia 10 years ago, Shoichi went to the future and ran into Byakuran. When he revisited it, hoping to change, it awakened Byakuran's ability to retain the knowledge of different parallel worlds. Byakuran used this knowledge to conquer and destroy several parallel worlds. Eventually, the future Irie arranged for the younger Shoichi's memories to be temporarily wiped for five years in order to gain Byakuran's trust, since the current world is the only one that is not ruled by Byakuran.