Fourteen-year-old Callum Silver sees dead people. It’s not a gift. His family thinks he’s crazy. Sometimes he thinks he’s crazy. He has no friends. He’s forced to live his life surrounded by nothing but the searing pain, sickening smells and desperate moans that accompany the murdered ghosts who seek him out. When he’s offered a place at Camp Wanagi, the ten weeks in the French countryside isn’t a vacation, it’s a lifeline. A way to meet others like himself and prove his ability can offer more than years of loneliness and expensive therapy bills. Run by a mysterious group known as the Oracle of Senders, Camp Wanagi brings together teens from around the globe who all possess the unique ability to see the dead. While Cal is relieved to find others like him, he learns quickly that not everybody experiences the spirits as he does. Some of the campers revere their abilities and don’t understand his hesitation, while others—like quiet bookworm Meander Rhoades—have good reason for wishing they could get rid of their ‘gifts’. While researching their final project, Cal and Meander find an unmarked grave which reveals aspects of their abilities neither knew existed, forcing Cal to decide if the torture of seeing ghosts is worthwhile and, more importantly, if being a part of the Oracle of Senders is necessary, dangerous…or both.

Callum Silver's second summer at Camp Wanagi gets off to a surprisingly good start. Seeing ghosts is a prospect more terrifying than ever. But this time, the campers are in paradise, and Cal is happy to join his fellow Shades for a summer on the beach. Especially now that there's one more among his group of friends. When Cal left camp last year, he would have hesitated to call quiet bookworm Meander Rhoades anything more than an acquaintance. Now, they talk constantly, and Cal is eager to spend his days by Meander's side. Thrown back into the world of the Oracle, Cal soon finds that the angry spirits he experienced last year were nothing compared to the ones lurking in this island paradise. But one thing that hasn't changed is the fact that some of his teammates are eager to try out the skills they've acquired and prove themselves worthy of one day becoming Senders—even if it means risking their lives. With each passing day, the stakes grow higher as attempts to battle spirits push the boundaries of the campers' capabilities, and Cal wrestles with the realization that his feelings for Meander may extend beyond friendship. Can he survive the summer and keep his relationships intact?

When Callum Silver arrives in Greenland for his third summer at Camp Wanagi, the only thing he feels is dread. Last August, camp took a terrible turn. Since then, things have only gotten worse. Mim is still in a coma. Meander is practically non-existent. And Cal’s not the only camper suffering from bouts of insomnia and night terrors. Because this isn’t just another summer with the Oracle. This year, the members of the Shade sector are turning sixteen—the age when the full aspects of their abilities finally come to fruition. Cal is terrified of seeing his first post-birthday spirit. But as the bright Greenland summer wears on, he discovers there are things far more disturbing than sickness-inducing ghosts. New revelations, changing talents, and daring missions twist Cal’s understanding of the past and alter his expectations for the future. But even when he thinks he’s finally got a handle on what it means to be a Sender, the summer’s final encounters prove more deadly than anyone expects. Cal’s not sure how camp is going to end. But whatever happens, one thing is clear—this is a summer no one in the Oracle is going to forget. Happy birthday, Shade…

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 what his world would look like without the Oracle in it. He can't escape the dead—can he really escape becoming a full-fledged Sender? And does he even want to?As the summer flies by amidst sector travels, new camper mentoring, and plenty of ghost sightings, Cal tries to distract himself from the future by focusing on the joy of having this last summer with the rest of Shade. But when the campers choose their final ghost, and Cal and Meander find themselves pitted against an entity more dangerous than any they've faced before, Cal can't stop wondering how the two of them will handle life beyond the Oracle—if they manage to make it through the summer alive. Return to Camp Wanagi—one last time.