"Long ago, two races ruled over Earth: HUMANS and MONSTERS. One day, war broke out between the two races. After a long battle the humans were victorious. They sealed the monsters underground with a magic spell. Many years later..."

"MT. EBOTT 201x. Legends say that those who climb the mountain never return."

you climb up the mountain, suddenly you trip over a vine and fall into the... Underground

UNDERTALE

(Name the fallen human.)

you wake up in a pile of sunflowers.