Adrien pushes the office doors open. He looks around the room before his eyes stop at the portrait of his mother. "Our best bet is the safe. We should try that first."
"On it, Commander," Plagg jokes, flying out of his holder's jacket as he phases through the painting. The model pulls the painting back as the safe swings open. The kwami rummages through papers. "Nothing interesting here."
"Except that book," He says, grabbing it, and flipping through the pages of old heroes and miraculous. "I still don't understand why my father has this."
Plagg holds up a drawing of two stick-figure parents and small child. He starts laughing and asks, "Look, this is so ugly! Whoever did this can't draw!"
"I drew that when I was five," Adrien whispers.
The kwami stares up with wide eyes. "D-Did I say ugly? I meant—a masterpiece! This belongs in the Louvre with the Mona Lisa!"
"Nice save, Plagg," Tikki mutters.
Adrien snatches the drawing from his kwami and sets it aside, closing the safe shut. "There's nothing in here. Let's look somewhere else." He pushes his mother's portrait back against the wall.
Marinette stares at his mother and smiles. "She was so beautiful, Adrien." As her eyes glance down, she notices certain grooves, different from the rest of the portrait. She steps forward and runs her finger over it. "Adrien, look. These marks..."
He turns around and places his hand beside hers, feeling, and their hands spread out to the rest. "That's weird. I've never noticed these before---"
They both dig their fingers into the grooves and activate the secret buttons. The floor opens and they jump together with a scream. "AHHH!"
The elevator takes them down and up, opening to a dark room. A big window opens up, light shining in, and exposes thousands of flying white butterflies. The pair look around with wide eyes as the insects fly around. Marinette reaches a gentle hand out as a butterfly lands on her finger. "This is more than enough proof that your father is Hawk Moth, Adrien." She looks over, noticing his frown, and sighs. "I-I'm sorry, but at least we know the truth now."
Adrien starts to nod. "I-I know, but..." He closes his eyes tight and starts crying. Marinette walks over and hugs him.
"It's going to be okay, Adrien."
An alert beeps on Mr. Agreste's phone. From the window seat of the plane, he grabs his phone and checks the notification. Camera surveillance of his lair extends to full screen, and he watches live footage of his son and his friend exploring. His eyes widen. This isn't good.