When Sheep and Duck think that Dog has a secret, they decide to figure out the mystery. As they secretly watch Dog, they discover he wants to build a word with the oo sound. But will they be caught before they can guess Dog's secret? Build a Word: "POOL" Although Whale may be big, her friendship with Sheep proves to be bigger, and they discover a way to continue to play together: they just have to build a word! Build a Word: "SUB"

Originally released by PBS, 2008. Streaming video file encoded with permission for digital streaming by Infobase on March 23, 2022.