Nerissa is kinda done with the whole being hunted and her brain being bashed in with a rock. And bashing their brains with a rock. So she's taking a vacation. She first convinces Noah to teach her how to fly a plane - Kai could have done it better, but she's not asking him for anything - and takes off for her much needed holiday in this empty world.
She crashes the plane somewhere out in the middle of the ocean and finds herself washed up a fucking desert island. She wonders how many times she drowned. Eh. It doesn't really matter. She's died enough times that she can't really feel it anymore.
Still. Desert island could be exciting. Time to explore. Hopefully, before the moon is fully out. Exploring and controlling the change would be a bit of a multitask.