The world's greatest young detective is leaving his neighborhood behind and taking his incredible skills on the road. Nate the Great and his loyal dog, Sludge, are flying all the way to San Francisco to visit his cousin, the famous secret agent Olivia Sharp. But when they arrive, Olivia is nowhere to be found, and a brand new case is waiting for them. A boy named Duncan has lost his favorite joke book, and he is absolutely convinced that the world will end if it is not found immediately. Nate agrees to take the case, hopping into a fancy limousine to track down clues across the massive city. From a bustling pancake house to the towering Golden Gate Bridge, Nate and Sludge follow a trail of sticky and complicated evidence. This exciting out-of-town adventure invites young readers to explore a famous city while cracking a hilarious mystery alongside their favorite sleuth.