Cassandra has been having a very bad year.
Well, actually, she's been having a very bad century or two, ever since that damn Doctor and his annoying assistant came and ruined her entire existence, but when one is as old as she is, the years begin to run together until they are no longer discernible.
Indeed, she has not had a good run of things lately. Living in this hospital has been no help either. She's bored out of her mind, and no one but Chip has paid her homage for being the last true human in a very, very long time. It is not an existence she really enjoys.
So when Rose Tyler shows up out of the blue at the hospital, she gladly decides to take her revenge.
Her year suddenly gets a whole lot better.
...
She should have seen this coming, really.
She saw the way Blondie looked at him at their first meeting, saw the sparkle in her eyes and the fascination hidden there. It's been a very long time since Cassandra has charmed a man, but she can still remember that first love: the thrill of being eighteen and enchanted by someone far too old for her. She knows that feeling. She remembers it well.
But that doesn't make being trapped inside Rose Tyler's body any less irritating.
Because Cassandra hadn't anticipated how strong Blondie's feelings really were for that annoying little man. And they shock her: the devotion this one, common human has for him is complete and unwavering. She will go anywhere with him, do anything, give her life a thousand times over for him. Cassandra doesn't know what to think of such things, but they keep floating out of Rose's mind and overtaking her thoughts until all she can think, breathe, feel is Doctor.
Really, once she sees him, it's all she can do to kiss the hell out of him. Not because she wants to. But because Rose's mind is starting to crowd hers a bit, and every instinct Rose has is to jump him, regardless of the time or place.
That ought to shut the little prat up, Cassandra thinks, satisfied.
It doesn't.
...
The jumping back and forth between bodies and all that running quickly become exhausting. Really, how do humans do it? She's only been up and walking for a little under an hour now and all she wants is to lie down for a moment. Or ten.
She glances at the Doctor as he speaks to the Face of Bo. Her heart flutters a little, but she knows it is not really her heart. As attractive a man as this Doctor is, she is not the one who so craves his touch.
She admires Rose Tyler's strength, briefly—the way she keeps fighting for control of her body long after others would have given in.
The Doctor was that way, too. Her brief escapades in his body were less fruitful, however; he knows better how to lock his mind to strangers.
Not that she saw nothing: a laugh, a flash of blonde that could only belong to the girl, and some ever-present sadness lingering in every corner of his being. He is odd, this lonely wanderer, but he intrigues her; she wonders at the things he's done, and the sadness.
Cassandra shakes her head and pulls herself out of her thoughts when the Doctor addresses her with his persistent demand for Rose.
She sighs. These two are obviously more trouble than they're worth.
...
When death comes, her last thought is not about the parties or how beautiful she once was or even the fear of what comes next. Instead, her final thought is of the Doctor and his blonde companion, of loving someone so entirely that he is all you think, breathe, feel, know.
In her last breath of life, Cassandra wishes she had known that kind of love.