Lewis McCartney is one of the main characters in the upcoming animated series, H2O: Mermaid Adventures. Lewis McCartney is a little genius, the kind of guy who surfs the school program effortlessly and wraps up his homework before everyone else. As a result, he comes across as someone who makes no effort. His career dream is to become an inventor and researcher in robotics. Although he's top of the class, he's not a nerd and the butt of every joke of his classmates: quite the opposite. He's a good-looking boy, he knows how to send back a joke, and he's not afraid of Zane, although he finds him exasperating. Lewis is the only person outside the trio of our heroes who knows about the spell over them.