As the daughter of Mermaid Aria (name changeable) have been living happily because Mermaids are ranked the number one of all species. Upon waking up and accused of killing her own mother Isabella, she was tied up and was transported to Lock 4. There a psychiatrist called Evan, welcome her to the "dorm" that is intended for Merman. It was decided that she will be the new caretaker, and with 15 guys within the room, she had to choose whose personal caretaker she'll become. With only three that she actually briefly spoken to, she choose...

[from Nabari no Blog]