Lewis Mcartney

Lewis Mcartney is the girls help throughout all of the series. Lewis descoveres that the three girls are mermaids in the second episode of the first series episode "Pool Party". Lewis is already a firend of Cleo and Emma and so can be trusted with the most important secret of their lives. Lewis also has a crush on Cleo, which turns into them going out.

This close relationship between the girls and Lewis is also one of the reasons that their secret was put in danger. Lewis is determined to understand the reasons why the girls transformed and so runs some tests on the girls and takes at instant interest about Mako island and the power of the full moon.

Eventually Cleo breaks up with Lewis and soon Charlotte is going out with him which creats tension between Cleo and Charlotte. Cleo regretts breaking up with Lewis. After a long and arduouse rivalry between Cleo and Charlotte, Lewis eventually breaks up with her and goes back out with Cleo.

Although they truly love each other, Lewis takes a place in an American school and leaves Australie and Cleo for his new life in America.

Soon enough through at Cleo, Emma and Rikki's graduation, Lewis returns to Australia, and to his true love, Cleo.