Make the card to wrap.
Fill it in, print it on card stock, cut on the outer edge and fold on the dashed line. It's 5 by 7 inches folded, and it's what they unwrap while the first letter is on its way.
You have been chosen.
The Keeper's Office, Russetmoor
Dear ,
A first-year student at Russetmoor has been placed in your keeping for . Her letters will come to your door twice a month, beginning with .
Read every word. Keep what you are sent. Do not write back.
Letters from Russetmoor, by Lamplit Post