After Mario had left to save the princess yet again, Luigi had been all alone with nothing to do but tend to the house. After going out to check on the mail, he finds a strange light glowing in the deep reaches of the forest around the house...

When an evil unknown is awaken in the depths of the earth, It's up to one undead to stop an upcoming age of blood, working with a peculiar set of ponies to help fend off such an age of aggression.