In the game Skyrim is a group of assassins who call themselfs the Dark Brotherhood. If you commit murder on a specific person (The Old bitter cold-hearted granny they call "Greloth the kind" who happens to run an orphanage. But the moment you enter you instantly realize that all the children get there is a person who is an emotional iceblock and overly exaggerated punishment for every little mistake.) you will get a note from the Brotherhood with the text "We know" and a black handprind. That's because killing Greloth was a job someone asked them to do, but you "stole" their contract. Then the next time you go to sleep you get kidnapped by the DB. You have to kill another random person and then you can join the Dark Brotherhood.