Ondina is a mermaid from the Mako pod who takes the bold step of leaving, with her best friend Mimmi, to save Mako Island – without the Mermaid Council’s permission. Ondina may be full of talent and determination, but she can also be reckless and willful, and has a problem listening to anyone who doesn’t agree with her. Just ask Sirena. Ondina refuses to believe her claim that Zac is not a danger to mermaids, so it’s inevitable they clash. But as they get to know one another, Ondina and Sirena start to appreciate and respect each other’s strengths.
Although she can be stubborn and single minded, Ondina is also fiercely loyal to Mimmi. They have been friends forever and Ondina is full of admiration for Mimmi’s extraordinary magical abilities.