Ever wonder what's behind that ""No Trespassing"" sign? Travel into the hidden world of Urban Exploration with the daredevil members of Backbone, the best UrbEx team in San Francisco. When they discover a secret bunker belonging to the long-vanished 1930s stage magician Blackhall the Incredible at the same time a young illusionist receives a mysterious package involving Blackhall's death in 1934, both groups dive into the mystery, not yet realizing it's about the change their lives forever.