The Twirlywoos are a family of bird-like creatures who leave their home - the Big Red Boat - to have adventures in the human world where they learn about concepts like full, underneath and up.
The four Twirlywoos - Great Big Hoo, Toodle-oo, Chickadee and Chick - have adventures both in the real world, and in their boat. They learn about a new concept each episode. Shy Peekaboo also lives on the boat, and joins in without the Twirlywoos knowing. The boat sometimes gets visitors, including the Stop Go Car and the Very Important Lady.