The TARDIS landed in the back garden. Not, mercifully, in the drive or on the front lawn, where the sudden appearance of a 1960s style police box would raise questions even an accomplished storyteller like herself would have difficulty explaining away.

As he had done before the Doctor once again walked her out of the ship, this time into the fading light of an early spring evening.

As they stepped out onto the grass Sarah turned and placed a hand on his chest. "Thank you, Doctor. Thank you for saving me."

The answering look in his eyes was so solemn that she wondered for a moment if there was something she had missed. "Thank you for saving me."

She breathed a shaky laugh and shook her head as the gravity of his reply seeped into the warm air around them. "Don't be silly."

He reached out and gathered up her hands, massaging her small fingers between his long, fine ones. His touch was like silk and she had to work to suppress a shiver.

"I mean it." His eyes drilled into hers as he leaned forward, his face inches from her own. He wished he could tell her, what she meant to him. That she was like no other – gracious and kind, independent and feisty, cheeky and wise. That nothing brightened his days more than hearing the smile that always seemed to suffuse her warm, rich voice. That he saw her spirit as steel sheathed in velvet, burnished bright as a sun yet gentle as a summer breeze, that he cherished her fearless heart. That she was a treasure he carried with him through all time.

But, as ever, the words wouldn't come. They were too small, too poor, to convey all the grandeur of meaning that he sought.

Instead he gave her the only gift he could. Without warning he leaned forward and captured her lips with his.

Sarah's world exploded. At the first brush of his mouth against hers every nerve in her body sprang to life, sending a tidal wave of emotion through her so strong that she swayed with the force of it. The rush of amazement, longing, release, joy, passion, and a not insignificant amount of lust threatened to overpower her. A soft whimper escaped her as she tried desperately to wrestle some semblance of control, and with a mighty effort she wrenched her lips away from his.

He stood, comically, with both eyes closed and lips pursed.

"What are you doing?" she gasped.

His eyes opened wide and he rocked back on his heels. "I'm, ah, fairly certain I was kissing you…"

"Why?"

"Because you always wanted me to."

Sarah's heart constricted. Evidently her stray, rambling thoughts in the fog of illness had inadvertently revealed more to him than she'd ever intended to say aloud. "You don't have to, Doctor." She swallowed hard, nearly overwhelmed with emotion.

He'd once considered her his best friend. She'd seen that in his thoughts. Seen the pride, the pleasure, that her friendship had kindled in him. She'd seen, too, that he loved her. Not in a messy, primal human way, but with an intense purity – like a chemical element or a prime number – that left her astonished and awed. She never dreamed – she never dreamed he might love her so much. Even now, the thought of it filled her with incredulous joy.

"It's all right. I understand, now," she continued in a rush, trying to make it clear that she really did understand. Sort of. "Time Lords don't love the way humans do."

He nodded in agreement. "We don't reproduce biologically, like you humans. Gallifreyan children are – were – created in vitro by splicing the parental genomes. No sexual reproduction, so no need for sex. No life partners, no lovers, no biological urge to mate. But –" he stopped, suddenly hesitant.

"But what?" she whispered.

He cocked his head at her. "What if I want to, to?"

She stared up at him. It wasn't as if the idea – the aching hope, the ardent desire – had never occurred to her. But she'd been absolutely certain it had never occurred to him. In a faint voice she asked, "Do you?"

"Yes."

This time Sarah closed her eyes and leaned into the kiss, feeling a lifetime of want and need and desire detonate in the sensation of his lips against hers. Her pulse began to race, her lips parting in eager anticipation as she felt his tongue flick against them. Moaning low in her throat, she opened her mouth and stroked her tongue along his, deepening the kiss, soaking up the wonderfully alien taste and feel of him. Their tongues danced together, sending sizzling, high-voltage currents back and forth between them and lighting every cell in her body on fire. How many nights had she dreamed of the Doctor kissing her like this… Her head swam with passion until she ran out of air and pulled back gasping.

The Doctor gazed down at her, his expression stunned.

Sarah bit her lip. She hadn't meant to put her whole heart into one kiss. But the Doctor had started it, and she had instinctively given him back everything she had.

"I can't –" he started.

"I know," she shushed him by pressing her fingers against his lips. He couldn't. He couldn't stay, he couldn't be hers, not in the way she'd always wanted him to be. He belonged to the universe – and she had always known it and honestly had always loved him for it, although sometimes the truth of it still cut through her like a knife.

She leaned in and kissed him again, this time more slowly and languidly, relishing the fact that she could. "You should go, Doctor," she said reluctantly as their lips parted.

"Alright." He nodded slowly, looking as reluctant as she felt, and pulled the TARDIS key from his pocket.

Sarah watched as he slid it into the lock. "Come back soon," she entreated softly, unable to believe she was about to let him fly away from her yet one more time.

To her surprise the Doctor slipped his hands around her waist and placed a feather-light kiss in her hair. "I will."

"Don't promise something you can't make come true." She'd meant to lighten the moment, but the words came out sadder than she intended.

He stared down at her, his hold on her waist tightening imperceptibly. "I promise." The look of determination in his eyes could level whole civilizations.

At once hopeful and fearful and unable to bear the weight of his solemn gaze, Sarah leaned forward and wrapped her arms around him, hugging him to her fiercely.

"You're an extraordinary being, Sarah Jane Smith," he whispered into her hair as she stood in his arms, trembling with love and loss. "My Sarah Jane."

Suddenly Luke burst into the garden at a run. "Mum!"

Sarah turned, gasping back a sob of relieved joy as her son threw himself into her arms. She embraced him tightly, closing her eyes. As she did the unmistakable sound of the TARDIS dematerialization circuits filled her ears. She whirled around – but he was gone.

"Until next time, Doctor," she whispered to the sky, her eyes filling with tears as the familiar pain of separation pierced her heart once more. But at least it wasn't goodbye. Not this time. Not while she had her memories – bright and crystal clear, like stars on a winter's night.

And not while she had her intergalactic cell phone.

She patted the small metal object in the pocket of her dressing gown, and then turned and threaded her fingers through Luke's.

FIN