Set in a fictional 19th century England, D.Gray-man is the story of Allen Walker, a 15-year-old boy who roams the earth in search of Innocence. Washed away to unknown parts of the world after The Great Flood, Innocence is the mysterious substance used to create weapons that obliterate demons known as akuma.

The battle on the sea continues, with the swarm of evolved akuma pressing hard on the Exorcists. Lenalee tries to tackle one akuma on her own, but realizes she can prevail only by unleashing the full force of her Innocence. Back on the ship Lavi prepares to call on a special attribute of his own Innocence. Will any of this be enough? Can the Exorcists hold on, or will they need help that may or may not come?