Hawkmoth/Gabriel finds out that Adrien is Cat Noir. He sneaks into his room at night and steals the ring off his finger. And he leaves quietly. Next morning.....
Adrien: Good morning, Plagg!
Adrien: Plagg? Plagg! Wait, where's my ring?!?!?! Oh no! (runs to camera room)
He types in the passwords and accesses the hallway camera and sees a tall, dark figure go in into his room. He can't see who it is in the dark video.
Adrien: I bet Hawkmoth took it when I was asleep! I have to warn Ladybug, but I don't have a Miraculous!......Or do I?
(he sneaks into his dad's atelier and opens the safe he somehow cracked)
Adrien: I can't believe I'm doing this.
He puts on the Peacock Miraculous and meets Duusu.
Duusu: Hello, I'm Duusu. Who are you?
Adrien: (sniffling up) Wait, do you have... ACHOO!.... Feathers?!
Duusu: Well, yes. I'm a peacock kwami. Of course I do.
Adrien: I need to get my ring back and I need..... ACHOO.....You to transform me, please!
Duusu: Of course, just say, Tail Span!
He transforms into Le Paon.
Adrien makes it to the Eiffel Tower, sneezing due to his allergies the whole time. At the tower... He activates the fan thing and it opens to reveal a phone. He contacts Ladybug and waits, still sneezing.
Marinette decides to transform and go on patrols. She gets a voice mail from 'Le Paon'. When she hears Cat Noir's voice, she rushes to meet him.
On the tower....
Adrien/Cat Noir/Le Paon is still sneezing due to allergies when Ladybug arrives.
Ladybug: Cat Noir?!
Le Paon: Ladybug! Yes its me, Cat Noir, but my ring was stolen. I found this..... ACHOO!....Miraculous and came to warn....ACHOOO!.....You... (sniffle).
And yeah, that's my idea. Rest of the episode is up to Zagtoon.