The Stone Tree stood in the middle of the square like an old friend with pockets full of stories. Under its wide crown sat Maja and Samir, drawing maps of the neighborhood's small mysteries: where the crows hid spoons, how the wind whispered through clotheslines, and who always lost a mitten. They loved to discover, but even more, they loved to do something to help.

One Monday, filled with the smell of freshly baked bread and bicycle tires, they decided. They screwed together a wagon with big, kind wheels and a handle heavy like a hand to hold. They painted it in summer stripes – lemon yellow, tomato red, and sky blue – and hung small, tinkling bells on the sides. Inside they built boxes with handwritten signs: Repair Box, Listener Box, Strings and Bright Ideas, Borrowables. There lay tape and string, magnets and scissors, crayons and a compass, a small pump, pruning shears, bandages, a magnifying lamp, and two cookies for anyone feeling low in spirits.

– We're rolling, said Samir, pulling the handle. – The Help Wheel is ready!

The first stop was the flower shop. Mrs. Rosalinda stood in the doorway with rolling eyes and an apron peppered with pollen grains. Inside the shop, it buzzed, not unhappily, but eagerly. Small bumblebees had gotten tangled among the bouquets and string stumps.

– They can't find their way out, she sighed. – And my fingers feel like blueberries from all the waving.

Maja took out a lavender sprig from Borrowables – they had gotten it from Mrs. Rosalinda last week – and Samir filled a low bowl with water, placing small stones in it as tiny landing places. They carried the bowl outside and held the lavender like a fragrant flag. The bumblebees followed, one after another, like when you whisper a secret word and everyone wants to hear it again. Outside on the sidewalk, they landed and drank carefully. Mrs. Rosalinda laughed with relief and stuck a seed packet into the Help Wheel.

– For you, she said. – So you can sow helpfulness wherever you go.

At the crosswalk stood Mr. Pindel, the tall traffic guard with cane and whistle. His sign had fallen, making the cars look more confused than dangerous.

– My sign has lost its back, he muttered.

Maja pulled out a clamp from the Repair Box. Samir screwed, Maja held, and the sign rose like a soldier after rest. Mr. Pindel nodded, gave them an exaggeratedly solemn salute, and let his whistle sing a little fanfare as thanks.

At the fountain stood caretaker Koko, looking like a cloud that had lost its rain. The fountain wasn't bubbling. Children sat on the edge and kicked at the gravel, as if the gravel was to blame for everything.

– The key ring, said Koko. – It dove down like a stone into the gutter. Without the keys I can't open anything: hatches, cabinets, or tricks.

Luckily, the Help Wheel had a magnet as big as a flat plum. Samir tied it to a string. Maja lowered it into the gutter and listened. Silence. Then a clinking, like a spoon against glass. Together they pulled up a dripping bunch of keys that glittered like small secrets.

– What fishing luck, croaked Koko, and turned a lock. The fountain cleared its throat, burped a little, and began to splash. A small company seemed to cheer at first – but it was a turtle that suddenly peeked up, surprised that there was a party in its home.

– You probably belong in the pond, said Maja gently. They rolled the Help Wheel like a small sedan chair, carrying the turtle to the park where the water was calm and full of small, glittery yummy bits. Caretaker Koko gave them an old ring key to hang as a memory on the wagon. It sounded ding-ding when the wheel bounced over the cobblestones.

On Old Lane sat Uncle Volter in his gateway. He usually played violin so the plaster on the houses smiled, but now the instrument rested quietly in his lap.

– The string broke, he grumbled. – And I can't find the new one. I think it ran away in shame.

Maja sat down next to him. Samir opened the Listener Box and pulled out two cookies, which they crumbled for the small birds. They looked at the violin case. It had more compartments than a wizard.

– If you were a violin string who was afraid, where would you hide? asked Maja.

– In the narrow compartment by the hinge, Uncle Volter was heard saying, now a little ashamed of his forgetfulness. And there, wedged under a soft piece of fabric, lay the string. Samir helped him tighten it. The violin tried singing, first carefully, then warm and steady. The melody that filled the gateway was something between the bumblebees' dance and the ring key's ding-ding. People slowed down, stood still, began to smile. The Help Wheel shone proudly without pretending.

Then it began to drizzle. Small, friendly drops dotted the ground. By the gutter stood Iggy, with three paper boats and an almost cry. He pointed at the street, where the water sought its own ways.

– We were having a regatta, he said. – But the river got crooked.

Maja and Samir rolled forward. They folded up a piece of cardboard as a ramp and taped it with big, safe pieces of tape, steering the water into a nice canal. The children cheered when the boats sailed like small, brave heroes. Just then, a splash and a clatter were heard from the market stall. Kiki, who sold fruit, had dropped a whole box of apricots. They rolled like small suns, and a lady was close to slipping on them.

– Apricot rescue! shouted Maja.

They formed a chain. Samir rolled the Help Wheel as a stopper, Kiki held up bags, and passing adults and children picked them up. Some apricots ended up in Borrowables as provisional wheel stops. When the street was fresh again, Kiki handed out apricot halves to all rescuers. The juice tasted like summer that wasn't going to give up.

Toward afternoon, the lights in the library blinked and became still. The doors stood fast, despite their pulling. Inside they saw librarian Inga, six preschool children, and Aisha from Maja's class. Aisha waved carefully, and the preschool children waved like pinwheels.

– Power failure, someone whispered. – The doors lock when it malfunctions.

Maja took out crayons and drew a giant hopscotch on the sidewalk, giving the wait a rhythm. Samir held up a paper against the window with big numbers: We are here. Inga wrote back on a whiteboard: Us too, all calm. To pass the time, Maja and the children outside began to tell stories with their hands. Inside the library, the preschool children answered with mouths that made oh and o, and Aisha's eyes laughed even though her mouth was shy.

– The back door! said Samir suddenly. – The one with ivy.

They ran around the building. The ivy lay over the handle like a green snake that had taken a rest. Maja pulled out the pruning shears from the Repair Box. Clip, clip, clip. Some passing adults came and pressed their hands against the door's edge. Mr. Pindel appeared with his long arm, and caretaker Koko with his ring key. With three pushes, the door opened with a sigh. Inga and the children walked out like a small parade. Aisha stood last and stopped by the Help Wheel.

– I want to help with it, she said quietly.

– Good, said Maja. – We have a Listener Box, and two more ears are always needed.

When the square filled with talk again, the Help Wheel felt bigger, though it was the same wagon. On its side, they painted a small turtle as thanks for the day's swim lesson. They hung up a new sign that read: What do you need? What can you do? People stopped and wrote with crayons: I can braid hair. I can carry heavy. I can tell jokes. I can fix flats.

That evening – when the Stone Tree just let the wind comb its leaves – the Help Wheel rolled homeward. The ring key sang, the bells answered, and the wheels remembered every cobblestone. Maja smiled. Samir smiled. Aisha held the handle and felt it fit her exactly. Help, they thought, is like a rolling song. It always finds someone who wants to sing along.