He hadn't expected that. Not for her to fall or for her to hit the ground or for her to be pass out on his bed. He should have taken her to the hospital. He should have taken her to get real medical attention. But he could not risk her identity being revealed to all of Paris. So he took her someplace safe and private where she could de-transform. He had not expected her to pass out though, and was now faced with a tough decision.
Chat Noir turned his back as Ladybug's earring sounded a last warning. Behind him, a warm glowing light lit up his peripheral and he knew that his partner was de-transformed. Chat wanted to look so bad; he wanted to know who the love of his life was. But it felt wrong to take away Ladybug's choice in the matter.
He squeezed his eyes shut in frustration. His own miraculous beeped. "Claws in," he commanded. His black suit and mask faded away and underneath he was just Adrien Agreste. He opened his eyes and his kwami materialized before him. Plagg's eyes widened when he saw who was behind Adrien. "What's she—"
A red kwami darted from behind his shoulder and silenced Plagg with a tiny hand to his mouth. "Plagg, don't reveal her identity!"
Adrien looked at the small thing with curiosity. "Are... are you Ladybug's kwami?"
She turned to him. "I am. My name's Tikki, and my miraculous holder is in need of help."
"I know, but how can I help her without revealing her identity?" Adrien pointed out their dilemma.
"Ah, true," Tikki thought for a moment, "we can't waste time; you're just going to have to find out who she really is. I give you permission."
As much as he wanted to know who Ladybug was, Adrien didn't want to look. He didn't care about having Tikki's permission, he wanted Ladybug's permission. But the kwami was right: they didn't have time. He felt frozen and rooted to the spot. Then he took a deep breath and turned his head.
He should have been surprised. He should have been shocked to find out that, this whole time, the love of his life had been one seat behind him every day. He should have been stunned that the girl of his dreams was someone he already considered a great friend. He should have been taken aback to discover that his lady was someone he already knew was incredible. But he wasn't surprised or shocked or stunned or taken aback at all. This made perfect sense. She was so selfless and caring and strong willed. Her heart was too big for that small frame of hers. Of course she had to be Ladybug. There was no one else it could have been.
"Marinette?" Adrien rushed to her lifeless body and knelt down. He gingerly touched her cheek, but she did not stir. He lifted her head and found red blood pooling on his bed. Feeling about her scalp, he found a two-inch gash that was sticky with blood. "I must get her to the hospital right now." He stood, determination gleaming in his eyes. "Plagg, claws out!"
The kwami spiraled into his ring and magic skittered up his body as he was transformed into Chat Noir. He scooped up Marinette into his arms, ran to the window, and jumped out into the night.