looked out over the fields, and beneath that, there was the kitchen wall, a mudroom door, and the grass that ran down to the barn.
Henry turned around and carefully poked at the knobs, then began picking chunks of plaster off the wall. Leaving a pile of dust on his blanket, he cleared out the area around both knobs and discovered a square metal door no more than eight inches wide, tarnished and stained green and brown under the dust. He leaned forward to take a closer look at the knobs themselves. His shadow wouldnât get out of the way, so he brought his lamp over onto the bed beside him.
The knobs were in the center of the door. They were a very old and dull brass, slenderâhardly knobs at allâwith filthy broad skirts. Henry took one in each hand and turned them. They spun easily and silently, but nothing happened. One large arrow stuck out of each skirt. Around the left-hand knob, symbols had been inlaid into the door, and around the knob on the right, numerals. The symbols on the left began with
A
and endedâback beside the
A
âwith something like a
G
. He didnât recognize the others. The knob on the right was simpler. It was surrounded by letters that he knew were actually numbers: I to XXII in Roman numerals. He counted the strange alphabet on the left and found that there were nineteen letters.
Henry had never been terribly good at math, but he knew he would have to multiply nineteen by twenty-two to find out how many possible combinations there could be to open the door. But knowing what he needed to do and being able to do it were two different things. After several attempts to do the math in his head, he left his room and went as quietly as he could down his stairs, to the second-story landing, and down again. He was less careful once he was on the first floor and made his way quickly into the kitchen, where he began rooting through the junk drawer for a pencil. He found a pen and a small instruction manual for a blender. He tore the back page off and hurried upstairs.
Back in the attic, Henry ran on his toes straight to his small room and knelt on his bed. The knobs had not disappeared. He scratched out the math on his bit of paper: 22 times 19 wasâ¦418. Henry sat back and looked at the number: 418 was a lot.
âWhat are you doing?â a voice asked from behind him. Henrietta stood in his doorway. Her thick hair stuck out from her head and a pillow crease ran down her cheek, but her eyes were bright. âI heard you coming down the stairs.â She stepped into his room, looking past him. âWhat did you do to the wall?â
Henry coughed and unswallowed his Adamâs apple. âI didnât do anything. It just cracked, and I was trying to see what was underneath the plaster.â Henry turned to the wall. âI found this little door. And it wonât open unless you know the combination, and I figured out that there are 418 possible combinations and only one of them will work, and Iâm going to try all of them until I get it open.â
Henrietta knelt on the bed beside him. âWhat do you thinkâs inside?â she asked.
Henry sat quietly for a moment. âI donât know yet,â he admitted.
âYes, but what do you think?â
Henry searched his mind for anything that could be kept behind small, hidden doors.
âSomebodyâs old things, maybe,â he said. âSocks or a pair of shoes. Some old fountain pens would be cool.â
âOh,â Henrietta said. âI was thinking there might be a map or a book explaining how to get to a secret city. Keys to a forgotten door or something. Maybe diamonds.â
âWell,â Henry said, âI think I should start trying to get it open. Iâm going to start backward. Iâll put this arrow on the last letter and then try it with all of the Roman numerals. Then Iâll do the next letter with all the Roman numerals, until Iâve done all