Undertale

"A long time ago, two races ruled peacefully over the Earth: HUMANS and MONSTERS. One day, a terrible war broke out between the two races. After a long battle, the humans were victorious. They sealed the monsters underground with a magical spell. In the year 201X, a small child scales Mt. Ebott. It is said that those who climb the mountain never return. Seeking refuge from the rainy weather, the child enters a cave and discovers an enormous hole. Moving closer to get a better look... the child falls in. Now, our story begins."