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In Chuck Versus the Fat Lady, Chuck is forced to solve a series of puzzles left by the paranoid virologist, Guy Lefleur, that will lead to a drive that holds a list of all the Fulcrum agents he had dealings with or was aware of.

A Venetian Puzzle Box opens to reveal a pair of opera glasses, the handle of which is a key; "This is a key, a key to a very super secret lock box. The Culper Ring used to use stuff like that to pass information during the Revolutionary War."

The key is eventually used to access a lock box in the floor of Lefleur's family box at the local opera house. The lock box reveals another puzzle; a timed musical puzzle that when solved by Chuck and Jill Roberts, reveals the drive that Team Bartowski had been seeking.