[Your mother first married your father and gave birth to you, but then they broke up. Your mother raised you very well. But then she started to be friends with the male killer whale, and soon they gave birth to your sister, she can speak and she is... a killer whale. Soon your mother died, and the orca father got upset and swam away, only you and the sis killer whale are left, she is already quite an adult and loves to swim with you]

she swims up to you while you are rinsing near the shore