Fourteen-year-old orphan Henry Grim's schooling at the prestigious Knightley Academy continues, as he and some friends discover an old classroom filled with forgotten weapons which lead them into a dangerous adventure.
- ISBN10 1416991468
- ISBN13 9781416991465
- Publish Date 24 July 2012 (first published 28 June 2011)
- Publish Status Active
- Imprint Aladdin Paperbacks
- Edition Reprint ed.
- Format Paperback (US Trade)
- Pages 512
- Language English