It's time for a field trip to Gold Country! Cody, Quinn, Luke, M.E., and Mika are the Code Busters—clever clue hunters with a passion for puzzles. The group of friends are excited to explore caves and learn about the gold rush, all while solving codes. But when Matt the Brat plays tricks on them and Cody starts seeing a mysterious figure with glowing red eyes, their field trip takes a turn. Will the Code Busters be able to figure out who the figure is and what it wants? And will they maybe even find Bigfoot?