The Missing: Treasures of Sirenes

The legend of Blue Orctic says that there's one treasure deep in the ocean guarded by Sirenes.

Krystel the princess of blue ocean in north went to the top of the water to see if there's a human roaming around there territory.

Krystel went to the isle near their castle. There she found couple of men. She sneaked through the water to hear what they are talking. She heard that the men are trying to steal the treasure. When she swam down she saw a man drowning. A human. She helped him from drowning.

Krystel swam back down to tell her father of what she heard. But her mind can't get away from the man she helped. As soon as she reports it to her father she immediately swam up. The man saw her and think the sirene is the one who helped him. He called her and introduced their selves to each other until they fell inlove.