prolog
What is visible in the dark

1.
A small but big wish
2.
Luck that no one knows about
3.
The back of luck
4.
Traces of erased songs
5.
On set
6.
Where luck passed
7.
One day later, two days later, three days later
8.
The time we have left
9.
In the dim darkness
10.
The owner of Lucky Sound Source
11.
The street I saw in my dream
12.
Where the sound sleeps

Epilogue
And you are lucky

Author's Note

A modern children's mystery novel that traces the truth behind a curse through social networks.

Yuna, a second-year rookie YouTuber brimming with enthusiasm, and Minjae, who has been active in the entertainment industry since childhood and runs a famous YouTube channel, are always bickering and having a good time.
One day, before summer vacation in the 6th grade of elementary school, Yuna finds a video on social media called 'Lucky Sound Source' and makes a wish to increase the number of YouTube subscribers, which leads to strange events.
Thanks to the power of Lucky Sound Source, his subscriber count increases in an instant, giving him a brief moment of excitement, but soon, malicious comments start appearing on YouTube and a pale girl keeps appearing in his nightmares.
To avoid the approaching curse of the lucky sound source, Yuna decides to solve the riddles in the sound source together with Minjae.
The two, who followed the clues scattered on the Internet, discover that the lucky sound source resembles the theme song of the popular children's drama 'Lucky Curl', and that a few days ago, volleyball club member Eunseo went missing after making a wish on the lucky sound source.
Who sang "Lucky Sound," and why did it end up circulating online? What's the connection between the theme song for "Lucky Girl" and "Lucky Sound?"

As you follow the story of digging through social media to find accounts and using various functions of smartphone apps such as music search and map view to uncover the truth about the curse, you will soon encounter an unexpected story.
An eerie curse threatens Yuna and Minjae with every passing moment, but when they finally meet the owner of the sound source and hear his story, they may gain the courage to overcome their fear.

A ghost story that captures the desires and darkness of the internet world that today's children can relate to.

"Lucky Sound Source" shows Yuna's true desire to increase the number of subscribers, and the Story King review said, "The fact that it doesn't try to judge children's desires is the most welcome thing about this work.
"They quietly listen to children's hearts and wait patiently" (judges Lee Hyeon and Kim Ji-eun) received praise. Yuna and Minjae's obsession with their social media subscriber count and their in-depth web surfing of information are relatable to today's children, who have adapted to the internet environment from the moment they were born. If you've ever managed a social media account and been concerned about responses, or been captivated by short-form videos, you'll easily relate to Yuna.
What if people suddenly flocked to my social media posts and left malicious comments? What if that video I thoughtlessly overlooked possessed a strange power and brought about a curse?

Author Cha Sam-dong said that he saw music videos circulating on TikTok with descriptions like, "If you listen to this song, your wish will come true," and "Everything will go well," and he felt a strange feeling when he saw disparate background music flowing over photos of different places, which reminded him of the story of "Lucky Sound Source."
The idea that the video contains a scary secret that will bring misfortune to those who make a wish.
The story of "Lucky Sound Source," which began with the imagination of the strange side that might exist beyond the ordinary daily life of the Internet world, invites young readers into a chilling and lonely ghost story.


The whole time I was writing, I was alone on the stairs that my ten-year-old self was afraid of.

Between the familiar and the unfamiliar, between the bright and the dark.

The memories of going up and down there, the moments of hesitation, and overcoming it alone.

I hope young readers feel the same way I did.
-From the author's note

Biryongso's new children's mystery novel collection, The Mystery

Biryongso presents a new children's mystery novel series, 'The Mystery.'
The stories are written at a child's eye level, yet are not trivial, capturing the hearts of young readers and allowing them to fully immerse themselves in the mystery genre.
As you follow the process of solving the mystery and read with the feeling of being a detective yourself, you can naturally develop the inferential thinking skills to find cause and effect.
The Mystery Series, a collection of children's mystery novels that will help children develop their thinking skills while reading fun stories that they can get lost in, will continue to be published starting with 『Lucky Sound Source』 and 『Detective Myeongaru』, the first winner of the Biryongso Sherlock Holmes Award.


It's amazing how such an exciting story can begin with just one song I happened to hear.

-Jeon Ga-ram (1st year, Gimpo Janggi Middle School)

This book is a thrilling mix of mystery novel and half a scoop of horror.
-Kim Eun-hyu (6th grade, Hwaseong Geumgok Elementary School)