Jake sat opposite Cathy and mashed his cornflakes into a sloppy mess. His head rested in his hand, and he'd hardly spoken.

"You'll turn the milk sour," Cathy said and gave up on her own breakfast.

Jake dropped his spoon and pushed his bowl away.

"I'm sure he's fine. Better than fine." She tried to sound convincing.

"How can he possibly be fine? He's lost somewhere in this enormous house. Maybe he's trapped in one of Flo's boxes. He'll starve to death. You don't know. A pile of rubbish could topple over and crush him. Or he could swallow a ball of fluff and choke."

Cathy stayed silent. Her brother had a point. Their nan was a hoarder, and she'd filled her house with clutter and junk. Every summer, Jake and Cathy stayed with Flo while their parents worked. It was a miracle falling boxes hadn't crushed one of them, or that neither of them had choked to death on the thick dust inside Topsy Turvey House.

Cathy stood, tying Flo's floral apron around her precious dress of stars, and began clearing the table. "I'll help you search for him if you dry up the breakfast bowls."

"Thank you, Cathy."

With that, Jake grabbed the tea towel from the hook by the kitchen door.

Ten minutes later, they stood in Jake's bedroom and studied the gnawed shoe box.

"We need to follow the clues like real detectives. If I were a mouse, where would I hide?" Jake scratched his head as though thinking hard.

The night before, Cathy had watched Chicken Nugget squeeze through the hole in the shoe box and scurry away, but she'd said nothing.

"Behind there." She pointed to the wardrobe.

Jake's eyes flicked between the shoe box and the wardrobe.

"Yes, of course. That makes perfect sense. Good detective work."

"I'll check this end and you check the other," Cathy said and knelt to peer underneath.

Jake lay on his tummy with his cheek pressed to the floorboards.

"Do you see anything?" Cathy whispered.

"It's too dark."

"Just a minute." Cathy fetched the bedside lamp and switched it on. She shone the light across the floorboards.

As she directed the lamp towards the wall, two tiny eyes sparkled.

"I've found him!"

The mouse, blinded by the bright light and startled by Cathy's yell, shot along the wall toward Jake.

"Catch him!" Cathy jumped to her feet, but Chicken Nugget moved like lightning and dodged Jake's hand as he tried to grab him. The mouse swerved right and bolted towards the open door.

"Cathy! Stop him!"

Chicken Nugget was too quick and shot past her before she could slam the door shut.

Sensing his freedom lay just beyond the hall, the mouse hurtled down the stairs.

"Jake, hurry!" Cathy giggled as she yanked open the door and chased the mouse down the stairs and into the drawing room.

Chicken Nugget ran as fast as his legs would carry him—until he came face-to-face with an intruder and skidded to a halt with his whiskers twitching. Was this mouse a friend or foe? Unsure, he froze.

Cathy also froze and stared into the enormous mirror.

"Cathy." Jake waved to draw her attention and jabbed his finger toward the mouse. "We've got him."

Cathy didn't move.

Jake was within grabbing distance when Chicken Nugget decided the intruder was the enemy and charged forward, baring his teeth.

"Come back," Jake yelled.

Before Cathy could stop him, Jake lunged for the mouse.

He tried to regain his balance on the slippery floor, but it was too late. He staggered and tumbled into the mirror.

Cathy screamed, bracing herself for the impact. But instead of smashing glass, Jake vanished.

She rushed to the mirror with her hands outstretched and ripples appeared beneath her fingers.

The portal between realms was still open, but not for much longer. She held her breath and followed her brother into the fairy realm.