The show centers on the interactions of Henry the Lizard, a green CGI anthropomorphic lizard with purple spots, and an unseen narrator. Each episode centers on a theme relating to the episode's subject matter, such as Henry traveling through prehistory in a time machine in an episode about prehistoric animals. Henry is usually faced with some kind of predicament or work, always relating to the episode's theme, which he resolves by the end of the episode, often learning a lesson of some sort in the process.