Volume 2 in the mind-bending new series from Gene Luen Yang! There's something lurking beneath the surface of Stately Academy -- literally. In a secret underground classroom Hopper, Eni, and Josh discover that the campus was once home to the Bee School, an institute where teachers, students, and robots worked together to unravel the mysteries of coding. Hopper and her friends are eager to follow in this tradition and become top-rate coders. But why...

Determined to learn the history of once-elite Stately Academy, Hopper, Eni, and Josh are challenged to outmaneuver Principal Dean, who demands that the team turn over their most powerful robot and threatening coding genius, Professor One-Zero.

Dr. One-Zero won't stop until the whole town--no, the whole world--embraces the "true happiness" found in his poisonous potion, Green Pop. And now that he has the Turtle of Light, he's virtually unstoppable. There's one weapon that can defeat him: another Turtle of Light. Unfortunately, they can only be found in another dimension! To open a portal to this new world, Hopper, Eni, and Josh's coding skills will be put to the test.