PBS KIDS Love Math and Science! Season 1 Episode 7 Codename Icky

In the watery depths of cybersite Aquari-yum, the kids and Hacker go in search of a giant cyber-slug, who feeds on pure energy. The kids and Digit travel underwater in two separate vessels, but Hacker has a listening device that taps into their communications system, allowing him to overhear their plans and track every move they make. The kids outsmart Hacker by devising a series of codes so they can send messages back and forth in secret - even though Hacker can hear what they¢‚¬´re saying. But unless the kids can reach the slug first, Hacker will use the slug to attack Motherboard¢‚¬´s circuitry and disable her once and for all!