The world's greatest detective is back on the case, and this time the mystery involves a very ferocious dog. Annie is trying to throw a birthday party for her fierce pet, Fang, but there is a major problem. She has completely lost her house key and cannot get inside to set up the decorations and treats. Nate the Great is not exactly excited about attending a party for a dog who scares him, but a good detective can never resist a tricky puzzle. With his trusty canine partner, Sludge, by his side, Nate begins to track down the clues. They must use all their logical thinking to retrace Annie's steps and figure out exactly where that key could have gone. As the clock ticks closer to party time, Nate searches high and low to crack the case. Readers will love following along with the clues and trying to solve the mystery alongside their favorite young sleuth. This story is perfect for kids who enjoy using their brains to uncover hidden secrets and save the day.