Booth and Brennan arrive at the Victorian bank accompanied by a DC beat cop. The cop leads Booth and Brennan to a locked vault. They watch as an FBI safe cracker breaks it open. Booth and Brennan enter the vault to find a steel labyrinth full of Masonic artifacts. They find an ancient Greek phrase on the back of the door, and Gavin Nichols' missing three million dollar violin. But the topper is a silver skeleton made partially of human bones. In fact, it appears that Gavin's valuable little pinkie is now part of the skeleton. Because of his body position, the group is suddenly curious about Hodgins' theories. The skeleton was deliberately posed in the "Widow's Son" position, a stance that holds deep roots in many secret societies, including the Freemasons. For the Free Masons, it represents sacrifice. And since Harkness was found with a dagger through his heart, it's now a question of who - and how many - have done the human sacrificing. There's still a lot of work to be done to find that answer.