When Jon and Tania attend a costume party at a museum full of ancient arms and armor -- relics that have been through bloody battles, or worse -- it doesn't surprise either of them to discover a ghost lurking in the shadows. But this particular ghost is on a mission, and if Jon and Tania don't help him, he just might become the warrior he was when he was alive, and that means trouble -- and danger -- for everyone involved!

Jon, Tania, and the Haunted crew are in New York City for a costume party at the Metropolitan Museum of Art. Among the fancy masks and disguises is the ghost of a 16th-century French squire who is determined to protect his sword--one of the museum's newest exhibits.