Fullmetal Alchemist: Brotherhood - episode 26 - 03 Oct, 2009

Edward and Ling face off against Envy. Edward, finding himself hesitating to attack, due to all the people embedded into Envy's body, gets swallowed. Meanwhile, Scar and May find Shao Mei with Alphonse and Gluttony and decide to follow them down to an underground tunnel, where they fight off several chimeras. Edward spots the philosopher's stone inside Envy, and, after seeing the missing piece from the ruins of Xerxes found in Gluttony's stomach, he conjures a way to escape. Bradley explains to Mustang how he was trained from birth for leadership and was injected with the philosopher's stone. Edward reluctantly uses the souls inside the stone to transmute himself and open the Gate of Truth to escape through. Edward finds Alphonse's body but is unable to bring it back, since it is not his. However, before the gate closes, he bursts through it, yelling to Alphonse's body that he will come back to get him someday. (Source: Wikipedia)