Hidden Expedition: Smithsonian Castle

https://www.amazon.com/Hidden-Expedition-8-Smithsonian-Castle-Collectors/dp/B00TRV4QFS Your old buddy and H.E.L.P. operative Sam calls you in to investigate a strange anomaly at the Smithsonian Castle. You soon learn there's more than meets the eye, and H.E.L.P.'s reach stretches back to the Smithsonian's historic founding. Unlock the secrets of time travel as you follow the clues into the Smithsonian Castle's hidden past.