Prende's Chronometric Lantern, Prende's Lantern, or the Muse's Lantern is known from fairy tales as a "magical lantern" created by Van Rijn that could manipulate time. To Violetta: "Tarvek was really into anything related to the Storm King, you know? All kinds of things, even fairy stories… There's this one where Van Rijn creates a magical lantern to free the Storm King from a castle where the sun never set." 
However, Agatha finds a passage in the Van Rijn notebook that seems to show the lantern may be more than just a fairy tale and she begins to suspect that it is what Margarella Selnikov was looking for in the Corbettite crypts of the Depot Fortress of St. Szpac.
Hoping he will be able to provide more information about the lantern or where it might be found, Agatha becomes even more determined to find Dio Zardilev, since she thinks the Lantern's powers might be used to free Mechanicsburg, now frozen in time.
She eventually discovers what appears to be the lamp in an abandoned Corbettite vault underneath Paris, connected to a glowing orb via power(?) cables and guarded by Prende herself; when the lamp is nevertheless from the cables, it is revealed that it was being used to hold Andronicus Valois himself in some form of temporal stasis. In the general chaos invoked by the breaking of that stasis, the damaged lamp is stolen away by rogue Smoke Knight Madwa Korel.