Demigods: In Paris (a Miraculous Ladybug and Percy Jackson crossover)

Yes, I went with Bag Lady

As soon as Ladybug got rid of Chat for the second time, she raced to the bakery and knocked on the door. She had to find a way to talk to Nino and Alya without revealing their identities to her other friends. It was bad enough that she'd already revealed them to each other.

"Ladybug?" Her mother gasped. "What are you doing here? Is Marinette okay?"

"Marinette's fine. I took her somewhere safe to hide, but Hawkmoth is attacking, and he, uh, seems to be targeting large gatherings. Marinette said there was a party here?"

"Yes, it's her birthday."

"Oh, well Happy Birthday Marinette, I'm sorry but I'll have to crash the party for now." Talking to her mother as Ladybug never got easier. "Do you mind if I take a couple of your guests to a safe place?"

"Of course, please come in." 

Ladybug made a show of counting the people. 

"Okay, I need you, you, you and you to come with me," she said, pointing. She noticed with a pang that they had finished the film and started another one without her. "I already got Marinette and Adrien to safety. The rest of you should be okay here in such a small group. Enjoy the party!"

Ladybug led her group of four outside. "Do you two have anywhere you can stay? Somewhere quiet?"

"Well... My house is empty," Juleka muttered, shifting shyly. Rose turned the colour of her namesake.

"Great. You two, stay here," Ladybug said to Nino and Alya meaningfully, before taking hold of Rose and Juleka and asking for directions. "I'll struggle to carry both of you, so do you mind holding hands? For safety, obviously." Ladybug cheered silently when the two girls blushed but linked their hands anyway.

When Ladybug landed back in front of Alya, the other girl was smirking. "Okay, who paid you to do that?"

"My sources asked to remain anonymous," Ladybug joked with a wink, then became serious as she handed them each their miraculous. "Hawkmoth is battling Chat Noir and two new allies at the Eiffel Tower. He's akumatised himself and is aiming to kill, so be careful. There's only so much my lucky charm can fix."

"What's got him so mad?" Carapace asked once he'd finished transforming.

"Um, we worked out his identity and tried to bargain him into giving us his miraculous, but it went wrong."

"You know his identity?"

"Yes, but he knows Chat's."

"Do you know who Chat is too?"

Ladybug couldn't help the blush that rose to her cheeks, "Yes."

Rena Rouge whooped. "LadyNoir is coming true!"

"No, it's not," Ladybug chided her. "He doesn't know who I am and it's going to stay that way. Now come on, we need to go."

The three of them hurried to the scene. Ladybug was surprised to see tentacles of water coiling around Hawkmoth. 

"A sentimonster?" She wondered, but then they landed on the platform and she realised that Hawkmoth was struggling against the water. "What? Are you... controlling that?"

"Yeah," Percy grinned at her from underneath a mask that looked like it was made of ice. It was transparent, but distorted his features enough to make him hard to recognise. Annabeth fought beside him, wielding a white sword and wearing a paper bag with eyeholes over her head. 

"What's with the masks?"

"You said you had backup coming, and there's only so much the Mist can hide."

"Do we have time to talk..?"

"Oh, yeah." Percy didn't even look over his shoulder as the water dragged Hawkmoth under again. "He's busy. Who are your friends?" He peered closer at Carapace and Rena. "Al-?" 

Annabeth slapped a hand over his mouth. "You have got to stop exposing people's secret identites!" She chided.

"Oops, sorry." 

"You know me?"

"You know her?" Chat asked, dropping onto the platform. He was clutching a wound in his side. "How come I'm always the last person to know about things around here?"

"Hey, Chat. Heard the cat was out of the bag," Rena winked. "Who are you?"

"I'm not going to tell you that," Chat glared at her. "Guys, this is Rena Rouge and Carapace."

"Nice to meet you dud- uh, guys. Who are you? If you don't mind me asking."

"I'm... huh, I need to think of a cool name. Aquaman's taken, right?" Behind him, Hawkmoth spluttered as he was let up for air, then dunked back under. "What did you call me earlier, man? Something wave? Hurricane? Tidal wave! That was it, Tidal Wave! Oh, and this is-"

"Don't say it," Annabeth warned.

"-Bag Lady."

"He said it," she sighed. 

"Hey dude, are you okay?" Carapace was looking at Chat's wound in concern.

"I'll live," Chat replied. "And if I don't, I've still got eight lives left."

"Man, that looks bad," Percy took a closer look, concentration slipping. "Maybe I could seal it temporarily?"

Chat was obviously trying not to freak out as water climbed his leg and pooled into his wound, quickly turning pink with blood. Percy clenched his fist and the ice began to freeze, when Ladybug saw that Hawkmoth had managed to get an arm out of the water.

"No!" She yelled, just as a spinning blade erupted through Percy's stomach.