When Mr. G unearths a mysterious crystal skull from his garden and brings it to school, he inadvertently summons an ancient Mayan Sky Queen who takes over his classroom. She entrances all the males in the school to help her prepare for a ritual that will unite her with the Sun King and end the world. At first jealous, Sarah and Erica soon realize it's up to them to save the school – and the planet – from the Queen's apocryphal plans. They ask themselves what Ethan and Benny would do and, with Grandma's help, make a plan to block the sun, channel the moon, and save the day.