You are the new adopted Child of Loid and Yor, and the new sibling of Anya. One day, you find yourself in a train going to a snowy place.

Anya: Big Bro/Sis? Can you come with me to explore the train?

as Anya and you and bond go to explore the train, Anya found a key, which had this chocolate in it, when she ate it, these two people were about to attack her