Episode 4 of The WONDERfools finally starts pulling back the curtain on the terrifying history behind the Wunderkinder project, and honestly, this was the episode where the drama fully hooked me. Between the painful flashbacks, the emotional character moments, and that breathtaking final scene under the Northern Lights, the series is starting to balance mystery, chaos, and heart surprisingly well.
The episode opens in the past as Dr. Ha first meets Ju-ran. Back then, Ju-ran struggled with a hearing disability, and Dr. Ha was the one who gave her hearing aids. At first glance, the scene almost feels warm and compassionate, but the show quickly reminds us that nothing involving Dr. Ha is ever simple.
Ju-ran remembers the devastating fire at Hawondo Lab and recalls how Dr. Ha ordered her, Pal-ho, and Ho-ran to stay hidden until he could get out of prison. Years later, after finally being released, Dr. Ha immediately resumes the Wunderkinder project and sends the trio to search for the mysterious Child of Eternity.
Back in the present timeline, Dr. Ha, Ju-ran, and Ho-ran confront Jeon-bok. Dr. Ha blames her for the horrors that happened years ago, accusing her, the woman once known as Madame King, of funding the experiments. Jeon-bok insists she only supported the project because she believed it would help sick children, not torture them.
But Dr. Ha is no longer interested in excuses. He demands information about the Child of Eternity.
Ju-ran then uses her powers to force information out of Jeon-bok, though Jeon-bok keeps insisting the child died years ago. Dr. Ha refuses to believe that because, according to him, the Child of Eternity could never die no matter how many experiments were performed on him.
That revelation leads into one of the episode’s darkest flashbacks. We finally see Un-jeong witnessing the brutal experiments performed on the young child. The suffering becomes too much for him to bear, and in a moment of desperation, he unleashes his powers to stop everything. That act ultimately causes the fire that destroys the lab.
In the present, Un-jeong wakes up from a nightmare reliving those memories. Even while asleep, he accidentally activates his abilities, causing destruction around the house. Meanwhile, Jeon-bok realizes Dr. Ha manipulated her into revealing information during their earlier confrontation.
At the same time, Chae-ni unknowingly catches the attention of dangerous people again. Outside, she tries using her powers because she wants to see the Northern Lights someday, a surprisingly innocent dream considering all the chaos surrounding her.
The next day, Chae-ni drags Gyeon-un and Ro-bin to City Hall for a street cleanup volunteer event. The three of them ask Un-jeong to help train their powers, but he’s emotionally distant and clearly frustrated. Things get even worse when members of the Church of Salvation suddenly appear nearby. Their presence immediately triggers Un-jeong, and he angrily pulls the trio away.
Instead of helping them properly, he tells them to figure out their abilities themselves by repeatedly forcing their powers to activate. It’s rough advice, but strangely enough, it works.
Elsewhere, Dr. Ha learns that another experiment involving Bong-pal has failed. Without hesitation, he orders the scientists to kill him. Yu-ran starts worrying that all of them will eventually be discarded once the side effects become impossible to cure, but Ju-ran continues believing in Dr. Ha and pushes the search for the Child of Eternity forward.
Meanwhile, Jun-mo meets with Jeon-bok and shows her CCTV footage from the previous night. In the video, Chae-ni is outside experimenting with her powers when Dr. Ha suddenly orders Pal-ho to kill her. Just before Pal-ho attacks, Chae-ni accidentally teleports away.
Not long after, Jeon-bok receives a strange phone call and quickly realizes the person standing in front of her is not actually Jun-mo at all. It’s Ho-ran using hallucination powers to spy on her and gather information about Chae-ni.
Ho-ran confronts Jeon-bok emotionally, accusing her of abandoning the children years ago. She again asks about the Child of Eternity and even uses her powers to intimidate her, but Jeon-bok refuses to break. Once Ho-ran leaves, Jeon-bok urgently tells Jun-mo to find Chae-ni before Dr. Ha does.
Back with the main trio, the atmosphere becomes lighter for a while as they discuss what they actually want from their powers. Chae-ni just wants to see the Northern Lights. Gyeon-un wants to become someone his daughter can be proud of. Ro-bin wants revenge against the bullies who humiliated him in high school.
The training scenes are actually some of the most fun moments in the episode because the characters slowly discover the “rules” behind their abilities. Chae-ni realizes she teleports whenever her heart rate spikes. Ro-bin’s powers activate when his emotions explode, while Gyeon-un sticks to objects whenever he lies or gets nervous.
Unfortunately, the fun doesn’t last long.
Pal-ho suddenly arrives at the junkyard where Un-jeong is supervising the cleanup work. Un-jeong immediately attacks him, but Chae-ni accidentally teleports directly into the middle of the fight. She quickly returns to get Ro-bin so they can help.
The battle sequence that follows is messy, chaotic, and surprisingly emotional. Chae-ni desperately tries teleporting everyone away but struggles to control her powers under pressure. Un-jeong reveals that Pal-ho is a true Wunderkinder, which makes him far more dangerous than the others.
Ro-bin and Un-jeong combine their abilities to fight back, but Un-jeong slowly weakens during the battle. Seeing him collapse, Chae-ni hugs him in panic, and suddenly teleports both of them away from the junkyard entirely.
At the same time, Ro-bin reaches an emotional breaking point and successfully stops a car that Pal-ho throws toward him. It’s probably the first moment where he truly understands the potential of his powers.
Then comes the episode’s most beautiful and tragic scene.
Chae-ni and Un-jeong suddenly appear beneath the Northern Lights, finally fulfilling Chae-ni’s dream. But the moment is heartbreaking because Chae-ni is bleeding heavily and slowly dying in Un-jeong’s arms.
Back at the junkyard, Pal-ho tries to finish off Ro-bin but fails. Elsewhere, Jun-mo searches desperately for Chae-ni and finds Gyeon-un literally stuck to the ceiling while panicking.
Meanwhile, beneath the glowing sky, Un-jeong desperately tries to revive Chae-ni.
And just when everything feels hopeless, Chae-ni suddenly wakes up.
Episode Review
Episode 4 finally delivered the deeper mythology I’d been waiting for. The series is beginning to connect the emotional trauma of the characters with the horrifying reality of the experiments, and it makes Dr. Ha feel far more terrifying now that we understand how far he was willing to go.
The reveal about the Child of Eternity also changes everything. It strongly suggests Dr. Ha successfully created someone who literally cannot die, and Un-jeong’s connection to that child explains why he destroyed the lab in the first place. His guilt and emotional isolation make much more sense now.
That said, I still think the biggest mystery is how Chae-ni, Ro-bin, and Gyeon-un developed powers at all. The drama keeps emphasizing that contact with the slime usually kills people, so the fact that these three survived still feels unexplained. Hopefully the show addresses that soon because it’s currently the biggest missing piece in the story.
Still, the emotional energy of the episode carried everything. Park Eun-bin continues to make Chae-ni endlessly entertaining, especially because her chaotic personality contrasts so well with the darker sci-fi storyline. And visually, the Northern Lights ending was easily the strongest scene the drama has delivered so far.
Episode 4 felt bigger, darker, and much more emotionally grounded than the earlier episodes, exactly the kind of momentum this series needed.
