Gigi examines the twelve tiny dollhouse books and twelve associated numbers, trying possible code systems such as substitution, coordinates, combinations, and Brady's suggestion of the Dewey decimal system. Knox checks the library shelves but finds no visible numbering system on the spines.

Using the magnifying glass, Gigi discovers that each miniature book has a readable title. The titles are all names from well-known books, including David Copperfield, Rebecca, Coraline, Anna Karenina, Carrie, Peter Pan, Matilda, Jane Eyre, Robinson Crusoe, King Lear, Oliver Twist, and Emma.

Gigi realizes the titles must correspond to real books in the library. When Brady identifies the number on Emma as fifteen, Gigi finds the full-size copy and opens to page fifteen, where underlined words appear. The team determines that the underlined words point to a shared letter; for Emma, the words all begin with L, and for Jane Eyre, Brady identifies C as the only common letter among the marked words.

Gigi, Brady, and Knox repeat the process for all twelve books, matching each miniature title and number to a page and extracting one letter per book. The resulting letters are L, C, R, E, E, T, I, H, B, P, O, and M.

Gigi quickly sees that the letters can form a phrase, first identifying “the,” then narrowing the rest into “rope” and “climb.” Knox assembles the full instruction, “Climb the rope.” As soon as the phrase is spoken, a stained-glass ceiling panel swings open like a trapdoor and a rope drops into the room.