D.Gray-man, Vol. 29

Kanda, Johnny, General Tiedoll, and Link listen as Allen tells of his past, about the incident at the Garvey Circus where everyone except he and Mana disappeared, then of how he and Mana journeyed together until Mana passed away. This leads the group to puzzle over the mystery of the holy war they've been fighting for so long. What is it really about? It soon comes to light that a clue may be discovered at a certain old bookshop.

Volume 29 of the D.Gray-man manga series by Katsura Hoshino.