Avery swims to the bottom of the pool and studies the blue-green mosaic through the circular glass clue. When the glass filters out the surface design, Avery sees a hidden pattern beneath it: a chessboard. The discovery confirms that Tobias Hawthorne embedded another layered puzzle inside Hawthorne House.

Avery connects the clue chain: the Queen’s Gambit, the royal chess set, and “Don’t breathe.” Ignoring Grayson’s warning not to play and wishing Jameson were beside her, Avery mentally maps the Queen’s Gambit moves onto the hidden underwater chessboard.

Avery dives repeatedly, testing the squares corresponding to those moves. The first two squares do nothing, but on the final Queen’s Gambit square, one tile turns and triggers a clockwork chain reaction. A compartment opens in the pool floor, and Avery forces herself to stay underwater long enough to pull out a flat sealed package before the mechanism closes.

When Avery surfaces, Jameson is there and pulls her from the pool. Their reunion restores their shared rhythm of trust, danger, and puzzle-solving. Jameson wraps Avery in a towel, gives her the knife from the shattered-glass game, and helps her open the vacuum-sealed package.

Inside the package is a fireproof pouch containing a faded photograph of three women standing before a large stone church. On the back, Tobias Hawthorne wrote “Margaux, France, December 19, 1973.” Avery immediately focuses on both the date and the place name, recognizing that “Margaux” could indicate a person named Margo or another layered Hawthorne clue.