Ella was balancing a block precariously atop a pile, tongue firmly tucked into the corner of her mouth, brow knotted in concentration, eyes giving Eric a small glance to see him nodding slowly. Taking a breath, she released the block and took a quick step back, cringing because she expected it to collapse, but it didn't. A single lined tower that stood a foot taller than herself remained between her and the boy who gave a hop and squealed.

"That's tallest!" Eric exclaimed, carefully making his way around it to stand at her side. "Ella, that's the tallest ever."

Looking around, she argued, "If we could get a stool, we could make it even taller."

"Ah, no, you two…" came the worried voice of one of the attendants, "Something like this comes down on your head and you'll be smartin' and I'll be hearin' from your parents."

Ella frowned as the woman began to pluck blocks off the top into her arms before she scattered them on the ground and pointed at them as a warning while Ella mumbled, "But it was tallest!"

"That it was, and I'm impressed Ella – don't think I'm not, but it's dangerous." She eyed her, "You do understand what dangerous is?"

Snorting, Ella gestured, "Blocks are not dangerous…" and her mouth closed tightly, lips pinched inwards as her eyebrows rose because she knew she couldn't tell the woman that being cornered by a Dalek or a Weeping Angel or a Slitheen was much more dangerous than a pile of blocks. So she reached for Eric's hand and pulled him towards the buckets of trucks and dolls so they could continue playing.

"You should tell them what real danger is," Eric whispered.

"I told you that's a secret," Ella hissed.

He shrugged, "Told me."

"You're my friend," she responded with a roll of her eyes, and then a smile in his direction. Because Eric wasn't like the other children at the daycare. He noticed the oddities in her stories and he asked about them. He was her very best friend.

"Look at those two, it's unfortunate they'll be heading to different primary schools soon. Clara's already registered Ella…"

The words stopped the truck in her hand from hitting Eric's and she shook her head slightly. They hadn't talked about changing schools. She looked at the boy who shrugged down at the toys and continued to swing his around and she asked quietly, "Eric, am I your best friend?"

He straightened, large smile brightening his pale face, "Of course you are, Ella."

Standing, she gestured to the back door that lead to the playground, "Then we have to run away."

Stopping just outside, he shook his head and argued, "We can't run away, Ella, it's almost nap time."

Frowning, she told him, "We're going to different schools soon."

"We won't see each other," he realized. Then he took a long breath and reached out a hand for hers and glanced at the attendants in the yard, telling her quietly, "We can probably get out of the side."

They nodded, giggling together, and rushed towards the gate on the side, Ella climbing on Eric's back to reach over and undo the latch before they began walking calmly down the sidewalk, neither saying much, simply chuckling nervously as they made their way through the small streets towards a park around the corner they both knew about. They would sit down and talk about what they would do when they got there – that was the agreement they made before they began to chat about the shapes in the clouds.

Clara had a hand clutched to her chest as they materialized around the two children several hours later and she exhaled a terrified breath to see them lying together in a pile, their small faces as still as their bodies. Without looking away from Ella, she asked in a quiet voice, "Doctor, are they…"

"Sleeping," he assured, moving to land his hands at her shoulders to rub at them, feeling the tension of receiving the call from the daycare that her daughter had gone missing. "Can't escape the dreaded nap."

She managed a laugh before she moved closer to them to kneel down and give them both a gentle shake, smiling when Ella shook her head and then opened her eyes, looking around herself curiously. "How did we get in the Tardis?" She asked.

"Ella," Clara stated firmly, lips dropping into a disappointed frown the Doctor could see was sending Ella's lips into a pout of understanding. "Mummy has been worried sick wondering where you are." Then she gestured, "And so have Eric's parents."

The girl stood and bowed her head, "I'm sorry."

"Why would you do that? You know you're not supposed to leave the daycare," she told her, head tilting sadly, because she knew her daughter had always been smart enough to figure out how to leave and they'd discussed why it was dangerous.

Looking to Eric, Ella explained, "We're going to different schools next term, aren't we."

Clara's head came up and she took a breath before admitting, "Yes, I believe you are."

"He's my boy friend," she complained.

"Your what?" The Doctor asked from the console as he set them down near the school.

"He's my very best friend," Ella cried quietly.

Pointing, the Doctor asked, "What do you mean your boyfriend?"

Clara turned, "Really, Doctor," before looking to Ella to nod, "Does it really mean that much to you, to stay in the same school as your friend?"

She nodded slowly as Clara reached for her hands and sighed.

"Maybe I could make a change…" she began, but Ella was already launching herself at her neck, arms wrapping around her tightly.

"But seriously, a boyfriend – she's not even five," the Doctor groaned.

Clara cradled Ella against her, kissing her temple as she listened to the little girl repeatedly thank her before she looked to the boy now staring up at the console with the widest eyes Clara had ever seen. They shifted slightly, to the Doctor and then he sat up quickly, dark hair standing on end as he asked loudly, "Is this the Tardis!?"

"How are you her boyfriend?" The Doctor shot back.

Eric wrinkled his nose and replied, "I'm a boy, and I'm her friend." He looked to Clara, "That's not what a boyfriend is, Ms. Smith?"

Looking from the Doctor to the boy watching her, Clara smiled and nodded, "That is exactly what a friend, who happens to be a boy, is."

Ella whispered into her ear and Clara laughed.

"Don't…" Clara replied quietly with a shake of her head, "Tell your father."

Pushing himself up, Eric moved towards the Doctor and peeked over the edge of the console before staring up at the man curiously peering down at him and he assured, "I know this is a secret, sir."

"A very important secret," the Doctor nodded, bending slightly to add, "Not very many people know about this place – can I trust you?"

Nodding vigorously, Eric asserted, "Oh yes, yes sir. I keep Ella's secrets," he turned and smirked at the little girl now being lifted up into the air, "All of them."

"All of them," the Doctor whined, "There are secrets, already?"

Clara laughed.

"She's four and a half!"

Settling a hand against Eric's head, Clara brushed her fingers through it and nodded to the doors, "Come on, your mum and dad are waiting at the school."

"Oi," the Doctor shouted as they made their way to the door. He toggled a finger between the children and grunted, "No more running away, you two."

They both shook their heads and he pushed off the console, walking towards them to pull Eric up onto his hip as the boy smiled at him and asked, "Could we have an adventure in your Tardis?"

The Doctor looked to Clara, to the pouted lips and the small shake of her head, and he sighed to Eric, poking his chest and then tapping his chin with his knuckle, "Not quite yet, but when you're older – if you keep this a secret and," he lowered his voice to whisper, "If you keep an eye on Ella so she's safe in school," he watched Eric nod, "When you're older we'll have adventures. Sound like a plan?"

"A good plan," Eric whispered back with a devious smirk just before they stepped out and the boy squealed, "We're in a cupboard!"

The Doctor rolled his eyes and called, "Of course we're in a cupboard – can't just land the Tardis in the middle of your classroom, can I? Wouldn't be a very well kept secret if I did that, would it!"

Clara pushed the door open, listening to the giggling at her shoulder, mirrored by the boy behind her. She knew it wouldn't take much to change Ella's registration, but she also knew she might be in for some interesting days ahead because the girl leaning against her had told her a secret. One the Doctor wouldn't like to hear. Ella knew very well what the difference between a boy friend and a boyfriend was and she'd whispered in her ear that she loved the little boy now commenting on the Doctor's bow tie.

A boy, she knew with a sly grin, who would be snogging their daughter in thirteen short years.