Far from her home, Sister Agenta travels aboard an ancient pilgrim ship, bringing good light into the endless darkness of space. However, after the captain responds to a mysterious distress call, she must deal with things far worse than the ignorance of her students - plague zombies infest the ship, wreaking bloody havoc on the ranks of the righteous. The only hope for Agenta, trapped on the lower decks and surrounded by death on all sides, lies in a mysterious black object found among a group of refugees... But will it help, and what will be left of the ship and passengers after those who came to the call of the artifact appear?