Oracle of Senders, Book 4 Seventeen-year-old Callum Silver is returning to Camp Wanagi for his final summer with the Oracle of Senders. Cal has gained a lot from his years of camp, including a steady relationship with Meander Rhoades. But despite all of the lessons he's learned, knowing this is the end of his time as a Sender-in-Training makes Cal uneasy. He doesn't want to face ghosts for the rest of his life. But he's not sure...