The Secret Room in School

Room 13 did not exist at my school. The door numbers went 12, then 14 — with nothing in between. Everyone insisted there was no room 13. But through the wall between rooms 12 and 14, I could hear something: typing. Old-fashioned typing, like a typewriter rather than a computer. One afternoon, I noticed the wall was slightly ajar. I pressed it, and it swung open. Inside was a tiny room containing one desk, one lamp, and one ancient typewriter...