Pokemon Best Wishes! - episode 14 - 22 Dec, 2010

Ash, Iris, and Cilan arrive in Nacrene City and head to the museum, but it is closed. Hawes, the museum's curator, explains that the museum is locked down because it is believed to be haunted. Ash states that he does not believe in ghosts, but Iris states it is possible. After the gang is given a tour, they are led to a sarcophagus and a death mask believing the chain of events are to be linked to the Mask Pokémon, Yamask. As they prepare to camp out inside the museum to discover the truth, Team Rocket meets up with another contact in Unova, who tells them they have to steal a meteorite from the Nacrene Museum. (Source: Wikipedia)