5Follow Sam, Egg, Gum, and Cat as they try to solve the mystery on their field trip to a notoriously mysterious military station, Area 99. After a few mysterious thefts, some scary claw marks, and more than a couple of strange noises, the junior detectives need to solve the case: could it really be an alien? Readers will love being able to choose from 12 possible endings and following the crew as they get out of some tight scrapes and some close calls.