They were drifting in the vortex peacefully, an exciting adventure behind them. The Doctor could still feel the past three days burning his muscles with aches and he laughed softly to himself as he walked through the maze of corridors that made up the Tardis interior – he hadn't felt this old in a very long time. He rubbed at his hands, worried the grease of working on the engines had lingered, and he sighed as he pushed at the sleeves of his dark jumper, reaching the door he'd been making his way towards.

Clara was just inside, curled around their son protectively, watching him sleep on their bed. A gentle smile was settled upon her lips as she stroked at the soft waves of brown hair atop the boy's head and then ran her knuckle along the stars that speckled the night sky of his little zip-up nightie. She should be asleep, he knew, because he knew the boy would wake all too soon and she'd be exhausted from the running and the fighting. He should remind her, he knew, but he watched her as she looked over their son instead.

Her mind relived the dangers and the wonder of the past seventy two hours, from the moment they stepped out into an arena of wildlife Aurelius had never laid eyes upon, to the moment they stumbled back in through those heavy doors, out of breath and laughing. Their son, a bustling bundle of babbles in his arms. They'd seen a lot worse, he knew, but he also knew she'd looked upon teeth that had dared to threaten her child and she'd suffered the bruises for the fight to keep him safe from them. And she thought, as she often did, whether or not this life were worth the threat of death.

All of his companions had an epiphanous moment at some point in their run together.

When their human minds slowly calculated risks and imagined lifetimes.

Clara, infinitely so.

"Look at him," she offered softly. "Sleeping so soundly after all of that. Dreaming of chasing butterflies with his granddad – did you know he visits him in his dreams?"

The Doctor uttered a quiet, "Yes."

She chuckled, head giving a small nod of acceptance. "He's so very little, and yet so very brave, Doctor."

"He takes after his mum," he stated, watching her smile down at her boy, fingers wrapped delicately around his midsection.

Aurelius sighed in his sleep and the Doctor could see the corners of his mouth lifting slightly as he continued sleeping, entirely aware of his mother's protective presence at his side. It calmed him somewhat, that the boy seemed to sense her, turning towards her before she'd entered a room, or ostensibly searching through walls for her after she'd gone, following the trail of her as she moved. His hearts skipped, thinking about how dangerously close she's come to death, yet again.

Leave the dying to me, he wanted to tell her. Instead he steadied the beating in his chest and he leaned into the door frame, leisurely examining his wife and child. He knew what she would tell him, knew she would explain his regenerations weren't a break-in-case-of-emergency solution to her potential death. She would remind him there were deaths he couldn't return from, but that he had more chance than herself of returning. The Doctor bowed his head knowing she'd weighed the odds of their lifetimes and she chose what was best for their son.

"He's been in the world as long as he was in the womb."

The words spread her melancholy through him like a poison.

"How long will he live?" She added softly, not for him to hear, but he heard it anyways.

He understood.

He understood all too well.

Pulling his jumper off and tossing it aside, he crawled into the bed beside Aurelius, bending to press his knees into Clara's while leaning into his palm, looking down at her, still concentrating on their boy. There were unshed tears in her eyes and he questioned whether this were some sort of delayed shock; he wondered just what the right words in that moment for her were. The Doctor needed her to know he felt her worry; he needed her to know...

Reaching to touch a set of cuts on her cheek, he sighed, "When you sleep, you whimper sometimes – lost in some nightmare I can't reach no matter how hard I try – and there are nights where I wish I could do as Aurelius does: walk right in to comfort you with an ill-timed joke, or an awkwardly too-long hug."

Clara shifted her gaze to him.

"When you sleep, I count the beats of your pulse against the skin of your neck and I ask myself how much longer do I get to see this magnificent creature live out her life with me before its cut short because she let me intertwine into it so thoroughly." He laid his head down to reach out for her, fingers slipping over her smooth skin to cup her cheek and watch her close her eyes as his thumb swiped at a tear. "When you sleep, I imagine a thousand lifetimes with you and I imagine a thousand ways those lifetimes could be taken from us and there are nights I find I mourn you while you're still here."

Eyes like the blackest holes stared sorrowfully as he gritted his teeth.

He looked to Aurelius, "How long will he live?" The Doctor covered Clara's hand on the boy's stomach with his left and he shook his head, "We don't ask ourselves such a question, Clara. We never ask the question because it allows for the possibility that he will end and he will not."

Smiling, she looked to the boy opening his eyes at them. The boy who gave them a gummy smile and called them quietly, voice still somewhere in his sleep. The Doctor watched her kiss her baby's forehead and he listened to his laughter. Aurelius reached to slap at their hands as his legs began to pump happily, waking to find himself nestled between his parents, but he stilled, looking from one to the other before gripping them both to sigh and close his eyes again, comfortable resting just a little bit longer with them.

"I love him so much," Clara told him quietly, voice cracking.

He rubbed at her cheek and leaned forward to meet her lips before pressing a kiss into their son's forehead, just as Clara had done. Sometimes he imagined their fears were compounded by their circumstances, but he knew deep down they were the same as all parents in a dangerous universe. Every so often, in the dead of night, a parent ponders the ugly notion that they might outlive their child and then they shake those thoughts away to replace them with hopes and dreams.

Aurelius Daniel Oswald, he often told himself, would live a grand and endless life.

He smiled, fingers stroking gently at Clara's as he assured, "I love him just as much, and between you and I and our love is the safest place anyone could be."

Aurelius gave a small jump, a quick, "Mum, dada," escaping him clearly before he giggled.

Looking to Clara and then at their boy lying before them, the Doctor hoped she could see the serenity in his wide blue eyes knowing the truth in his father's words. He laughed with her as Aurelius uttered a series of gibberish syllables at them, a question for them that settled mischievous grins on all three members of their odd little family, floating out in time and space.

Where shall we go next?