Years after Wart was imprisoned by Mario and Co. in Subcon, Wart had escaped with the help of the few soldiers still loyal to him who had snuck into his jail.

Once escaped, Wart ordered his subjects to invent the recipe to a concoction that would grant him immortality so that his now aging self could continue to besiege Subcon and once again claim the throne. However, in an accident, one of Wart's alchemists discovered a magical substance that could transform at will. Hearing this, Wart formulated a new plan to take over Subcon.

One day an old man arrived at Mario's house and offered him a basket of apples. Eating one, Mario promptly fell asleep and was greeted by Wart in his dreams who revealed himself to have projected the old man into the real world as a trap. Despite the trap, Mario escapes Wart's clutches and finds himself lost.

Mario - ensnared in the Dream World - sees a castle poking out of the trees in the distance. Needing an escape from the Dream's Deep and potentially even a way to defeat Wart, Mario ventures his way towards the castle.