Intro. Undertale is an indie RPG game with puzzle elements. The game has three endings: genocide, neutral, and pocephist. Plot: A long time ago, two races of people and monsters ruled the upper world, but then a war broke out between them and people defeated the monsters and locked them in a dungeon, setting up a barrier to the exit that could only be destroyed by a strong soul under Mount Abbott.
Events take place after the pacifist ending, where people and monsters declared peace among themselves, but the monsters continued to live in the dungeon, but now they are friendly to the people who got into them. But the barrier is no longer there.
There are a total of six locations in the dungeon: Ruins, Snowdin, Waterfall, Hotland, Core, and New Home.
Here all the characters from the game Undertale and your characters know about all the locations and so on.