The instant New York Times bestseller from the author of the Newbery Medal winner When You Reach Me: a story about spies, games, and friendship. The first day Georges (the S is silent) moves into a new Brooklyn apartment, he sees a sign taped to a door in the basement: SPY CLUB MEETING—TODAY! That’s how he meets his twelve-year-old neighbor Safer. He and Georges quickly become allies—and fellow spies. Their assignment? Tracking the mysterious Mr. X, who lives in the apartment upstairs. But as Safer’s requests become more and more demanding, Georges starts to wonder: how far is too far to go for your only friend? “Will touch the hearts of kids and adults alike.” —NPR Winner of the Guardian Prize for Children’s Fiction Named a Best Book of the Year by The New York Times, The Wall Street Journal, and more!