 The prisoner in his adjoining cell—Herbert, the Man in the Iron Socks—tells Arthur that the Guild is creating miniature creatures, and helps Arthur retrieve the keys to their cells from the sleeping guard.Meanwhile, Willbury, Marjorie, and several members of the Laundry disguise themselves as boxtrolls and enter the Underground, where they locate Arthur's grandfather, but are caught in the traps used by the Guild to capture Underlings and taken to the laboratory.Marjorie recognises an enlarged version of her stolen invention—now revealed to be a size transference device.