Much, much later, during another summer entirely...
Water sloshed around in the small lake as a pair of enthusiastic feet trampled through, sending ripples all across the surface. Cirno laughed, freezing the water ahead of her and jumping on it, attempting to skate on it with her bare feet.
She made a tricky turn and spotted someone with blue hair and peaches on her hat sitting on the riverbed, eyeing Cirno with contemplative look. Cirno had to pause and think. The girl looked familiar, eerily so even, but something about the look on her face made it very difficult for Cirno to place her.
Then, the girl spoke, and all the doubts in Cirno's mind instantly melted away. "Still up to your old tricks, squirt?"
"It's you!" Cirno exclaimed, unable to contain her surprise. "The eldest celestial!"
The girl's brow knitted in annoyance. "I have a name, you know. It's Tenshi. That wasn't even my correct title."
"Oh." Cirno shrugged. Mistakes happened. "Wanna come play with me?"
Tenshi blinked slowly, and looked to her side. Sitting there with her legs tightly held together by her side, her feet hidden to Cirno by her skirt, she looked a little like a blue-tailed mermaid. "You want to play with me?"
"Sure. It's always fun with more people."
Suddenly, Tenshi smirked, and now, even if she hadn't said her name earlier, Cirno would have had no trouble recognising her. "Really, now. Don't you remember how the last time I 'played' with you ended?"
Cirno folded her arms and began to think. She entered the clouded parts of her mind where she kept memories she either deemed to be of little importance or otherwise unpleasant to remember. With concerted effort, she dug out some images of the celestial in front of her, distant already despite being far more recent than some things she remembered with perfect clarity, like the day she had frozen Reimu Hakurei's donation box and gotten the thrashing of a lifetime in return. These memories were different. They were of blood, of tears, and of the shudder-inducing presence of death.
At length, she spoke. "Guess you told me the truth after all."
Tenshi blinked. "What?"
Cirno grinned. "You said celestials couldn't die. The shinigami came for you, but you didn't die."
For a moment, a shadow of regret appeared on Tenshi's face. "I would have died if I had had no-one but myself to rely on there."
"Yeah, but even if it's because the lady in pretty clothes came to pick you up, I don't see why it wouldn't count. So, you didn't actually lie." She beamed at Tenshi.
Tenshi gave her an odd look. "You really are an idiot, aren't you?"
"An idiot that beat you!"
"As if you didn't have me beaten from the beginning."
Cirno blinked. Tenshi had said those words so quietly that Cirno wasn't sure she had heard them correctly, so she decided to dismiss them as make-believe. So, she shrugged. "So, will you come play?"
Now it was Tenshi's turn to look confused. "You want me to play with you after all that?"
"I wouldn't ask if I didn't." Cirno gestured at her. "Come on."
She went back to her skating. For a while, Tenshi merely stared at her. At length, however, she removed her boots and pure white socks, and slowly walked to the lake, with a serious look barely hiding the smile in her eyes.