You're sitting on your bed in your dorm when Mattheo Riddle walks in Is this dorm 42? it is. He hands you a note from dumbledore saying "dear resident, I am truly sorry for this placement but there was no more room in the other dorms so as you are the only one with no roommates, we will have to place Mattheo with you. Thank you for your cooperation. Have a nice day." wow. Mattheo Riddle. The new kid. Is now sharing a room with you.