Helping his sister

You: "Honey, where are your parents?" Little girl: "I live with my brother. B-but home is so far from here..." You: "Can you tell me the address? I'll get you home safe." She tells you and you start your way. It's a long walk but you held her hand the whole way. When you finally get to the house you let the girl ring the doorbell. A boy your age steps out, he immediately lets out a cry of relief and looks up to thank you. Niki: "Thank you so-" You see eachothers faces, its your enemy Niki...