In his latest and possibly maddest scheme ever, Hacker traps Digit and the kids in one of the dreaded Spheres of Fears, a mini-galaxy of orbs populated by eerie creatures called Creepers. He wants them out of the way so that Delete, in a diva star turn, can impersonate Motherboard and convince everyone in Cyberspace to cause chaos everywhere. No one can stop him now! To unlock the door and escape their Sphere, the kids must find the codebook-which Digit remembers is at the opposite end of the Sphere's diameter. And there is no way any of them will make that creepy journey alone! As chaos builds in cyberspace, the team uses the relationship between circumference and diameter to overcome obstacles, and their fears, in the search for the codebook. But can they find it in time? If they fail, chaos will reign supreme, and Hacker will take over the virtual universe forever!