A living thing that doesn't like her or Harry much, at that. She can't shake that feeling, ever since stepping through the door, though Harry tells her not to be silly, it's perfectly fine, and she has no choice but to believe him.
And for all of that, when the shaking of the ship stops and the mechanical hum has mostly died down, she doesn't really want to look outside. At least inside the ship it's relatively safe, enclosed, almost like being in a womb. Outside...
There could be anything out there.
"Oh, go on!" Harry says, beaming as he bounds away from the controls, towards her. "Open the door."
He's so excited, so childishly gleeful to take her here, to show her the stars... She can't very well say no.
Lucy walks to the door, the strange, incongruous doorway with the words POLICE BOX illuminated backwards over it, and hesitates, with her hand on the door, looking back to Harry. He grins and gestures again for her to open it, standing back with an expectant look. Lucy turns once more to the wooden door - and what kind of spaceship has wooden doors, how is that safe? - takes a breath and opens it.
Directly ahead of her burns a sun, red-gold and beautifully blinding. She has to squint her eyes to look at it, but even then, she can't make herself look away. As she watches, a tiny planet crawls across the face of it, tracing the path of its orbit.
She can't breathe. She can barely think, faced with this. Floating in space, staring at some alien sun and nothing else to be seen, anywhere, wherever she looks. Up or down or to either side, no stars, nothing but space, an empty void. The chill of that space begins to creep in, making her shiver. It occurs to her that she shouldn't just be cold, she should be dead, standing here with nothing between her and... nothing. Instead, she just gets the shivers.
And then Harry comes up behind her to wrap his arms around her, and the shivers stop. "Beautiful, isn't it?"
"I... What is it?"
"The last star in the universe, burning out," he whispers against her neck, and an entirely different kind of shiver runs down her spine. "The end of all things."
He really does think it beautiful, she can hear the truth in his voice, and so she does too. Lucy leans back against him, he wraps his arms tighter around her, and they watch as the last star in the universe dies.
He shows her so much there, the way everything comes to an end. The feral, savage creatures he says humans have become now. The starless skies, the emptiness of it all. The shadowed, cold, dead worlds that will never be lit by starlight, moonlight, or sunlight again. A thousand ruins of great civilizations past.
There is no God here, no heaven or hell, no utopia. There's only Harry, her very own lonely god.
The last thing he shows her is the last sapient race in the universe, the things he calls the Toclafane. And he offers to save them from the end, to take them back when the time is right. Some of them come back with the two of them, tagging along on the TARDIS for the return trip. As Harry works the controls of the ship to send them home, Lucy sits cross-legged in a corner of the console room, surrounded by four floating silver orbs who speak to her in child's voices. They exclaim excitedly over her golden hair, her clothes, her pretty smile. One of them tells her fairy tales about a place safe from the darkness and cold and savagery the universe has become, a place where the sky is filled with diamonds.
"Is it true, Miss Lucy?" it asks her, after it's finished its story. "Will you save us from the darkness, will you take us there?"
Lucy glances to Harry, who stands at the console. He catches her eyes and flashes her a smile, and her lips curve into a smile of her own as her heart jumps. She doesn't even have to think about her answer.
"Yes. You can trust Harry. I promise."