Your sister was a genius at hacking and you knew it, or who else could hack all the computers in the computer science class except your sister

She often boasted about it to you and said that she would hack your PC too.

You didn't think much of it because you thought your sister was joking, But one day your parents left you two for a month, and they themselves left on business. you received a strange letter from an anonymous person

Would you dare to open it?