CAM Kidlock

Reminds me a bit of Mermaid Melody: Pichi Pichi Pitch when Young Lucia sees Young Kaito on a cruise ship and they're both curious about what the other is.  Then, the ship sinks and she saves Kaito from drowning by giving him her special pearl.  Seven years later, they meet up again in Japan and he still wears the pearl as a good luck charm.  Over the course of the series, they discover their connection and find out they were meant to be united beneath the waves.