Hunter x Hunter Movie 1: Phantom Rouge

Leorio Paladiknight and Kurapika investigate a boy with scarlet red eyes, believed to be a member of the extinct Kurta Clan, of which Kurapika is the only known survivor. Kurapika is attacked by someone claiming to be his childhood friend, resulting in him losing both eyes. Leorio treats Kurapika's wounds and sends for Gon Freecss and Killua Zoldyck to help retrieve his eyes, which leads them to the infamous Phantom Troupe, the group responsible for the Kurta Clan massacre five years prior.