She's lying to herself about why she came here.
She told Flo (and even without their telepathic link the cat knew it was a lie) that she wanted to go to the Castle because it was the only place she knew that wasn't home. She didn't want to go home, she said (the only part of her winding explanation that was believable) because home reminds her of her family, and her family remind her of the other family she could have had. But she didn't. She had no-one, anymore; she had Flo, of course, but having part of your soul follow you around, snapping up mice and fish, doesn't really count.
But Flo didn't say anything, because she knew that Ellie knew that Flo knew that Ellie was lying, and that was so complicated that she had to take a little kitty nap while her blond fairy was packing her bags for the journey. When she awoke, with Ellie pacing the hall (the fairy knew better that you should never wake a sleeping cat, they don't take to it), she stretched out, flicked her tail, and pretended like she didn't know anything, because that was much easier.
For both of them.

The journey was simple, and once Ellie had got far enough away from Jasper and his new 'friends', it even became easy, and she had a few brief hours of enjoyment. But that quickly faded; she was getting further away from her toxic brother, but closer to a land which might not even remember her, not properly. Closer to a boy, a man, who she has wronged too many times for her to want to count them. She tried to focus on the beauty of Shaman, on the majestic landscapes and wonderful fairies with awe-inspiring abilities, but with every mile closer she flew, his face flashed in her daydreams more often. She can block her mind against intruders, but not against her own thoughts, though they are often worse.

Touching down outside the walls of the Castle, she sighs, placing Flo on the ground and healing the deep scratches the cat has made in her arms and torso. One day Flo will have her own wings, Ellie hopes, but for now she has to carry the cat and deal with the pain afterwards (I can't help it, you know I hate flying. Even with wings I'd rather you carried me everywhere.) Lazy animals.
Ellie catches herself as she begins to head towards the buildings; she only knows one room, and she doesn't even know if the owner is the same anymore. And if he is the same, he is unlikely to want her appearing, as if from nowhere, yet again, her bright blue eyes never able to convey just how sorry she is that one more time she had to leave him.
She grabs hold of a low wall as her mind blackens, and sits before she faints, finally overwhelmed. She doesn't know what she wants; with Jasper it is easier, he makes the decisions and she just follows along, good little sheep of a sister that she is. But she made one decision, one life-altering change, and she didn't think through the consequences.
It's time for her to grow up, truly. She just needs a minute to sit, with the grey cat curling around her legs and the bustle of the kingdom filling her ears.

i o d i n e .
kiss me,beneath the milky twilight.