Poopie found a wardrobe she had never noticed before. It stood in the corner of the attic, tall and dark, with one broken hinge on the left door. She walked closer. The wood was scratched and old. It smelled of cedar and dust and forgotten things. Poopie reached out her hand and touched the brass handle. It was cold - and it wiggled.

She pulled the door open slowly. Inside were old coats - heavy wool ones that smelled of grandparents and winter. Beyond the coats, darkness. Poopie pushed the sleeves aside. One step in. Two steps in. The coats tickled her nose. The floor creaked. Then - the back of the wardrobe was not there anymore.

She fell. Not fast. Not scary. Slowly, gently - like a leaf in the wind - she tumbled through colour and light and a sound like bells made of starlight. Blue. Gold. Pink. Swirling, swirling. Then - WHOMP.

Poopie sat up. She was sitting on top of a giant pink mushroom. It was springy, like a trampoline. She bounced once, just to check. Yes - definitely springy. Around her, other mushrooms rose into the sky: purple ones, orange ones, blue-spotted ones - each with a tiny house perched on top, smoke curling cheerfully from little chimneys.

She was in a city. Not a city like home. A city built on mushrooms, connected by wobbly rope bridges and spiralling staircases that wound up and up and up. The sky was the brightest blue she had ever seen. The flowers were pinker than any flowers she knew. Everything was more - more colour, more light, more wonderful.

A flamingo in a red uniform rushed past. His feathers were very ruffled. He was singing at the top of his voice. "A visitor! A visitor! From the world above! Oh what a tiz-tiz-tizzy! Remarkable, wonderful, dizzy-making love!" He tripped on his own feet, caught himself, and rushed on. Poopie stared after him with her mouth open.

"Excuse me," said a small voice. A rabbit in a blue waistcoat stood beside her. He held a little notebook and a very tiny pen. "You must be the visitor," he said, wringing his ears with worry. "Oh my. Oh my, oh my. I was afraid you'd come before I was ready." He bowed three times very quickly. "I am Clover. I will take you to the palace. Please follow me. Carefully. Very carefully."

Clover led her through the mushroom city. Creatures stopped to stare - furry ones, feathery ones, scaly ones - all with wide curious eyes. A blue cat with three tails waved politely. Two tiny hedgehogs in top hats bowed. A round orange creature that might have been a pumpkin (but wasn't) offered her a flower. Poopie waved back at all of them, grinning.

"This is Lalaland," said Clover proudly. "Every mushroom has a different neighbourhood. That blue one is the Bakers' Quarter - they make pies that float. That striped one is the Library - the books read themselves aloud at night." "And that big golden one?" Poopie asked. Clover stood up very straight. "That," he said, "is the Royal Palace."

The Royal Palace was the grandest mushroom of all. It glittered in the sunshine. Its gates were tall and shimmery, like frozen waterfalls. A rainbow bridge led to the entrance - a real rainbow, solid enough to walk on. Poopie put one foot on it carefully. It held. She put the other foot. Still held. She walked the whole rainbow bridge with her arms out, grinning.

Inside the palace, two very large capybaras sat on thrones made of woven flowers. They were wearing golden crowns. The crowns were slightly too big and kept slipping sideways. "Welcome, Poopie!" boomed the King, adjusting his crown. "We are so very glad you have come," said the Queen, and her voice was warm and kind. Poopie curtsied - she was not sure how, but she tried.

They gave her tea that sparkled. And cakes that tasted like her favourite dream. And a cushion that was exactly the right softness to sit on. For a little while, Poopie forgot everything - forgot home, forgot the wardrobe, forgot anything could be wrong anywhere in any world.

Then she noticed the Queen's eyes. They were kind. They were warm. But they were also - worried. Just a little. Just in one corner, where she thought no one would see. Poopie saw.

The Queen leaned towards an advisor and whispered something. Poopie only heard two words. "Missing soldiers." The Queen noticed Poopie looking and smiled quickly. But Poopie had already heard. And she was very good at noticing things others missed.

Lalaland was the most wonderful place Poopie had ever seen. It had mushroom cities and rainbow bridges and sparkling tea and creatures with three tails. But something was wrong. She could feel it - just beneath all the colour. Like a shadow hiding inside the sunshine.

Poopie looked around at the glittering palace, at Clover wringing his ears, at the Queen's hidden worry. She thought: I did not come here by accident. She straightened up tall. Whatever was wrong in Lalaland - she was going to help fix it. She did not know how yet. But she was going to try.