Cybersquad must stop Hacker from activating his newest creation, Gigabyte, before the light of the midnight moon, or else Dr. Marbles mind will be transferred into the monster, and Hacker will learn about all of Motherboard's secrets. The kids and Digit know Hacker is in a castle on a spooky, Halloweenish site called Castleblanca. Unfortunately, Motherboard wasn't able to specify which castle he is in. The kids must survey the residents of Castleblanca to pinpoint the exact location where Dr. Marbles is being held captive.