Her parents got killed, because they were evil. She got scared of the monsters and ran away. The girl didn't notice a big rock. Alice tripped and fell. She fainted while she was falling.
After 3 days of just laying on the floor, she woke up. Right in front of the girl standed Asriel, the king. This is how the conversation went:
Asriel: *pulls out a sword and points at Alice* Who are you? What are you doing here? Are you evil?
Alice: Please spare me Mr. Asriel, I mean no harm! I checked my soul, it's green and grey. I know that green is, it's kindness, but what's the gray part?
Asriel: *takes back sword* the gray is probably fear. But you don't need to fear. We won't harm you if you won't harm us.
Alice: Thanks for the explanation!
Asriel: What's your name?
Alice: It's Alice.
Asriel: Well, Alice, follow me.
Alice: Okay.
At Toriel's house:
Asriel: Mother! Guess who I found?
Toriel: I'm coming! Is that a... a... A child?
Asriel: Yes Toriel. It IS a child. She won't hurt us. She's kind.
Toriel: Come with me child. What's her name?
Asriel: It's Alice.
Alice: Mrs. Toriel, where are we going?
Toriel: I'm going to heal you. And bake you a pie. Go to Asriel, he will show you your room.
Asriel: Come, Alice. I'll show you your room.
In the room
Asriel: Go, get a nap. Sleeping heals. Where are your parents?
Alice: ....they are..... dead...
Asriel: Sorry for the question... Now sleep, Alice.