The North Aegean island of Chios is home to one of the most treasured and rare natural products in the world. Barry travels to the south of the island to witness the miracle of the weeping mastic tree, a phenomenon known only to this part of the world. Barry visits two of the unique and stunning fortified mastic villages, and gets lost in the labyrinth of streets designed to confuse invaders. In the north of the island, he visits the abandoned and haunting hilltop village of Anavatos.