On a trip to the zoo, Team Mystic encounters plenty of rare Pokemon. There are Abras, Mankeys, and Butterfree everywhere, not to mention a gazillion PokeStops. How lucky can a group of Pokemon GO players be? Then Gianna loses her lucky Pokemon-catching cap, and their fortunes take a turn for the worse. Now the kids have to stop looking for Pokemon and start looking for Gianna's favorite cap. Team Mystic is on the case! But every clue the friends follow seems to lead a dead end, and soon they find their hopes of finding the cap fluttering away. Can an encounter with Butterfree help them find the lucky cap? Or has their luck run dry? Fans of Pokemon GO will cheer for Team Mystic this exciting third book in the Unofficial Adventures for Pokemon GO Players series!