Memories of Carvalhal's Palace -Haunted Encounters is an Augmented Reality (AR) location-based game which involves players in uncovering the mystery behind the haunted aspects of a museum premises. The game deployed at the Natural History Museum of Funchal makes use of mobile interactive AR and gaming strategies to promote the engagement of teenage visitors (digital natives) in museum experiences. Through this game, the audience embarks in a journey through the museum spaces, collecting scientific information about selected exhibits, while interacting with their tridimensional (3D) AR models. The audience's interactions with the museum exhibits are rewarded with pieces of a map, which will guide them to a hidden location, the scientific library of the museum. There participants can finally unlock the mysteries they have been summoned to solve. The game's goal stems from the fact that digital native teenagers are identified as an audience group that is often excluded from a museum's curatorial strategies [1] and as consequence, they appears to be generally disinterested in what museums might offer [2]. In this article, we present the description and rational behind Memories of Carvalhal's Palace: Haunted Encounters mobile gaming application and then discuss the results of first empirical tests performed to evaluate the usefulness and usability of the game.