A plagued world where humans are able to turn into their past lives using a substance called "Catalyst". Their past lives could've been animals, plants, or even elements. Strangely, a mysterious disease spreads and it transforms humans into mindless monsters instead.

Drayden and his aunt are going on a trip to visit his father which he hasn't seen in ten years due to the "Walrusen" disease. Unexpectedly, their traveling is halted by pirates and they become test subjects for "Obscure" doctors. What will be the fate of Drayden and his aunt?