When the human falls into the Underground, they aren't met by anyone; the Ruins have been abandoned. As they wander through, all they can find are small piles of dust. Soon, they exit the Ruins and head into Snowdin Forest; the result is the same until they reach the barricade Blue had made. They then meet Lucario, who explains where they are and who he is. They shake hands, and he takes them into Snowdin. The only residents of Snowdin are Lucario and his younger sister, Blue, who takes a great interest in the human when they first meet.
After the human is shown around, Lucario leaves to go into the abandoned restaurant. This is when Blue first shows signs of being...'different'. She makes multiple threats towards the human, telling them to stay on Lucario's 'good side', or else she'll kill them. When Lucario returns, Blue goes back to her normal, energetic self. The human then leaves Snowdin, heading quickly into Waterfall. They find more piles of dust, and even some panicked notes in the few houses residing there. They mention that a skeleton-like creature was coming to kill them.