How it happened in Ladybug's imagination:

Adrien trudged down the slushy park sidewalk, hands in his pockets, kicking the harder chunks of dirty snow, just to see how far they would roll. It was a lonely Saturday afternoon, and everyone else was too busy for him. He wished someone would come and rescue him, someone he could spend the whole day with, laugh with, but no one else was here. Just the snow banks and the biting wind.

He sighed, pushing his hands deeper into his pockets, hunching against the cold. If only a special someone were here, to make him forget all his worries. Someone heroic and beautiful and smart. Someone who could sweep him off his feet.

Someone who loved him.

But he was the only person in the park. He turned up his coat collar and kept his face to the ground.

Which was really too bad, because he missed the only hint of what was about to happen. A flash of red, arms around him, a deep thud of impact. The force of his fall landed Adrien in the snow bank, Ladybug cradling his head protectively, all hints of cold gone.

"Hello, Monsieur Agreste," she said, drawing back, but not too far. (That wasn't true. Any distance was too far from her.) "I don't know if you saw, but there was a horde of fans sneaking up on you."

They were cocooned inside the snow, completely hidden. Ladybug was here, like an answer to an unspoken prayer. Sunlight filtered through their domed ceiling, low enough that his hair brushed it when he spoke.

"Fans?"

She lay in his arms, right where he'd always wanted her. He didn't know how he'd gotten into this position, not quite sitting, with Ladybug lying on top of him, her face so close to his, but he wasn't about to complain. She was so wonderful and so brave, risking everything daily, sacrificing so much for the city. He couldn't imagine her struggles, and that made him love her more. Love? Yes, it was definitely love.

"Yes," Her voice fell to a whisper, and he thought for a second that they were so connected she must have read his mind. "Fans. I saved you from them. They're right outside. They might hear us."

There had been no one. He was sure of it. "I see," he said, matching her flirty tone. "Thank you for saving me. I'm grateful."

"Of course. Anything for you."

He couldn't stand it anymore.

"I love you," be blurted.

Ladybug gasped at the sudden declaration, and maybe it was too bold, but he couldn't help himself. He wanted to be selfish, just this once. Tomorrow, he would share her with Paris again, but for right now, he wanted her all for himself.

"And wonderful, and so kind, and so smart. You're the most beautiful woman I've ever seen. You are everything I ever wanted and more. I love you." He tightened his hold on her waist, dragging her up until her lips reached his. They kissed and kissed until Adrien thought their snowbank would melt. And then they kissed some more.

How it actually happened:

From her hiding place behind a statue, Ladybug watched Adrien trudge through the park. It was a nice day, but too cold for most people, and they had the whole place to themselves. Perfect for the surprise she had planned.

The sidewalk curved toward her, and as soon as he was level with her, she pounced, practiced pickup line on the tip of her tongue. She collided into his side, and they flew in a jumble of limbs, landing face first into the snow. The force of their fall collapsed the snow bank, and she was grateful they were alone in the park, where no one could witness how Adrien had to pull her out from under the snow's crushing weight to rescue her. Ladybug sort of wished he'd left her buried, blind and deaf to what was happening.

He brushed snow off the back of his neck.

"That was so much more romantic in my head," she said, face in her hands.

Adrien turned, wide-eyed, snow still stuck to his gloves. "What?"

"You heard that?!"

A slushy clump dripped off his elbow. Ladybug ran.