In the evening, a big yellow moon hung over the town. A telescope stood in the window of Lila's room, and crayons, star stickers and a sky map were spread out on the carpet. Lila corrected the sparkly star band, Olek pulled up a stool and added the missing comet cloud to the map. Cat Pixel purred and fanned his tail like an antenna. - Can you hear? - whispered Lila, as something quietly beeped in the silence. Pixel stopped his tail. From the red walkie-talkie on the desk came: beep... beep... beep... beep! The rhythm was like a song, but different from any they knew. Olek put his ear to the loudspeaker and rubbed his chin, as his dad did when he was devising something. - 'It's not a storm. It's someone talking to us,' he said in a very serious voice. Lila glanced through the telescope. One tiny star was flashing in exactly the same way: beep... beep... beep... beep! The flashes formed a pattern, like a skipping rope that has its own pace. - You have to answer," Lila concluded. In the garage, their bubble rocket was waiting. They had built it with Daddy from lightweight panels and soft seats, then decorated it with clouds, stickers and silver tape. Bubble had a round window like the eye of a big fish and a dashboard full of buttons. One of them, silver and shaped like a blob, just flashed the same rhythm. - He can hear too,' whispered Olek. Lila slipped a soft blanket into Piksel's backpack. They put on their helmets from the costume box and checked their belts. A sticker on the door read: Start only when hearts are calm. - Hearts calm? - Lila asked. - Calm as a pebble in the pocket - replied Olek and smiled. Pixel murmured: rrr. Snap! The bubble moved gently, as if taking a deep breath. They heard a soft bruuum, and the house, street and garden disappeared beneath them like a picture in a book being flipped through. The space turned dark blue, then ink and then all the way to black, but full of scattered crumbs of light. - 'Welcome aboard,' spoke the soft voice of Bubble, as if a huge cushion was speaking. - I have a map for you. The destination is flashing. A map of the sky unfolded on the screen. Someone had drawn a bright dot on it, which pulsed. Bubble flashed the seatbelt icon. - Fastened - said Lila. - Tied,' added Olek, glancing at his shoelaces. Pixel dragged himself in his backpack and looked with eyes as round as moons. They flew among the flickers. On the way, they passed a satellite with panelled wings, which waved a short "bziuuut" at them. They flew past the rings of the planet, which looked like giant hula-hoops, and past a cloud of tiny crumbs, which drummed: tic-tic-tic. Bubble then unfurled a luminous umbrella that smelled like summer rain. - Wonderful is this sky,' Lila sighed. - And quiet. - Quiet, but listen - nodded Olek and tuned his ears. - Beep... beep... beep... beep! Louder! The closer they got to the flashing dot, the more the signal resembled a melody. A pencil-drawn shape appeared on the screen next to the dot: like an envelope. Only this envelope pulsed with light, like a jellyfish in water. - A star letter? - Lila was surprised. - To whom? Bubble bubbled cheerfully. - I detect letters on the envelope. In light it said: 'Lila and Olek'. Olek opened his mouth. - Who knows what our names are? - Maybe someone who looks at the same stars," Lila said quietly. The rocket braked next to a bluish cloud of dust, soft as cotton wool. In the centre of the cloud swayed a transparent envelope with a star seal in the shape of a tiny, glowing star. - 'I'm bringing the grasping arm closer,' announced Bubble. A small, shiny handle ending in a net slid out from the side. It moved slowly, gently. Lila held her breath, and so did Olek. The pixie stopped purring and froze, as if it had suddenly become a small, grey statue of a cat. Grid touched the envelope. The seal flicked and replied with a short: "piik!" Suddenly someone knocked on the rocket window. Tuk-tuk. Tuk-tuk! Lila and Olek jumped up. They turned their heads simultaneously. Just outside the window floated a small craft, light as a kite. It had a tail made of ribbons of light, and the cabin was like a bubble of water with a shiny rim. Inside sat a creature in a ridiculous polka dot suit. It had a round helmet, and inside the helmet were two large, curious eyes that shimmered like a puddle after rain. The creature moved the fins on its sleeves and drew a heart on the mist glass. Then it pointed to an envelope and waved. - It can see us! - whispered Olek. - 'And she knows how to draw hearts,' added Lila, feeling herself getting warm under her helmet. Bubble muttered cautiously. - 'I'm answering a connection request through the guest window. Secure, with an extra air bubble. I can open the letter lock and let the letter in, and then.... A new button they hadn't seen before flashed on the desktop. It was green and had a smiling star drawn on it. - 'If we press it, it opens the guest window? - Lila asked. - 'Just a little bit, in hello and good morning mode,' confirmed Bubble. - Still safe. An extra bubble ready. The signal turned into a melody that sounded like snow creaking and a bicycle bell at the same time. The seal on the envelope glowed brighter and a luminous shape appeared on its surface: a small hand that waved in greeting. The pixie wiggled its whiskers and quietly 'meow' said to the backpack. - What do we do? - Olek looked at Lila. - Together? - Together,' Lila replied and held out her hand. Their fingers intertwined and they hovered over the green button with their other hand. Behind the glass, the dotty creature knocked again, this time three times: tuk! tuk! tuk! Her eyes shone wide, and the tail of her stateroom waved like a ribbon in the wind. - 'Attention, countdown to the opening of the letter lock,' announced Bubble in a soft voice. - Three... two... The melody became even more beautiful, as if someone was playing tiny bells. The green star on the button shone so brightly that it became like noon in the cabin. Lila and Olek were taking air into their lungs, ready to...