Boy, With Caution Wiki: Cast, Story, Episodes & Where to Watch
Boy, With Caution (Korean: 소년, 주의) is a 2026 South Korean BL romance drama starring Ryu Se-il and Ha Jeong-hoon. The series follows Jang Ki-woo, a temporary high-school teacher whose carefully controlled life begins to fall apart after he meets Lee Hyun-jae, a troubled 21-year-old student who has become isolated from the people around him.
Produced by Nakwon Mansion and distributed by Heavenly, the Korean drama is scheduled to premiere on September 30, 2026. The series consists of 8 episodes and is scheduled for weekly releases.
Boy, With Caution – Quick Wiki
| Category | Details |
|---|---|
| Title | Boy, With Caution |
| Korean Title | 소년, 주의 |
| Previous Title | Mind the Boy |
| Country | South Korea |
| Language | Korean |
| Year | 2026 |
| Genre | BL, Romance, Drama |
| Format | K-Drama / Web Drama |
| Episodes | 8 |
| Runtime | Around 25–30 minutes per episode |
| Premiere Date | September 30, 2026 |
| Release Day | Wednesday |
| Platform | Heavenly |
| Production Company | Nakwon Mansion |
| Distributor | Heavenly |
| Director | Lee Son-eum |
| Main Cast | Ryu Se-il, Ha Jeong-hoon |
| Original Language | Korean |
| Status | Upcoming / Premiering |
Nakwon Mansion’s production information confirms the title, main cast, director, genre and September 30 release, while current drama listings report an 8-episode first season.
What Is Boy, With Caution About?
At the center of Boy, With Caution is Jang Ki-woo, a temporary teacher who has built his adult life around being careful.
Ki-woo once had ambitions of becoming a certified teacher, but an inappropriate rumor involving a student four years earlier changed the direction of his career. Since then, he has moved between contract teaching jobs while trying to maintain the image of someone who never gives other people a reason to criticize him.
His next assignment brings him to Nakwon High School.
That is where he meets Lee Hyun-jae, a 21-year-old student who has been held back and has developed a reputation that makes most people at school want to stay away from him.
Instead of immediately accepting what everyone says about Hyun-jae, Ki-woo asks a much simpler question: why is he behaving this way?
That small difference in Ki-woo’s attitude becomes important to Hyun-jae.
For someone who has spent a long time being treated as a problem, being genuinely noticed by another person begins to mean far more than he expected.
Jang Ki-woo and Lee Hyun-jae
The main relationship drives the story.
Jang Ki-woo, played by Ryu Se-il, is an adult who has spent years trying to avoid controversy. His past has made him extremely cautious about how other people see him.
Lee Hyun-jae, played by Ha Jeong-hoon, is almost the opposite. He has become accustomed to being judged before anyone understands him.
Their personalities create an unusual dynamic.
Ki-woo sees something behind Hyun-jae’s reputation, while Hyun-jae becomes increasingly attached to the teacher who treats him differently from everyone else.
The problem is that Ki-woo is Hyun-jae’s teacher.
That teacher-student boundary is central to the drama’s conflict and is one of the reasons the series carries themes involving rumors, professional boundaries, emotional dependence and forbidden romance.
The Anonymous Chat App “Anyone”
One of the more interesting elements in Boy, With Caution is the anonymous chat application called “Anyone.”
Ki-woo uses the app to talk about personal things that he cannot easily discuss with people in his everyday life.
Hyun-jae eventually discovers the application on Ki-woo’s phone and deliberately joins the platform.
The two begin communicating while protected by their anonymous identities.
This creates an unusual situation: they can become emotionally close online while their real-life relationship remains complicated by the fact that Ki-woo is Hyun-jae’s teacher.
The anonymous conversations therefore become another layer of the story, separating what the characters know about each other privately from what they can acknowledge publicly.
Story and Main Conflict
Ki-woo’s life has been deliberately ordinary.
After the damage caused by the old school rumor, he has chosen stability over ambition. He wants a quiet career and a life that attracts as little attention as possible.
Hyun-jae disrupts that plan.
Everyone around Ki-woo warns him to stay away from the student. Hyun-jae is considered troublesome, and his reputation precedes him.
But Ki-woo notices that the version of Hyun-jae described by other people does not completely match the person he encounters.
As Ki-woo begins paying attention to him, Hyun-jae realizes that he is receiving something he rarely gets from other people: genuine attention.
That emotional connection gradually becomes more complicated.
The series asks whether two people who understand each other’s loneliness can keep their feelings separate from the boundaries surrounding their relationship.
Main Characters
Jang Ki-woo – Ryu Se-il
Jang Ki-woo is a 32-year-old temporary high-school teacher.
He was raised by a single mother and grew up with the idea that he needed to live without giving others any reason to criticize him.
Four years before the events of the drama, an inappropriate rumor involving a student damaged his career plans.
Instead of taking the teacher certification examination, he began working from one temporary teaching position to another.
At Nakwon High School, he meets Hyun-jae and finds himself unable to simply ignore the student everyone else has already judged.
Lee Hyun-jae – Ha Jeong-hoon
Lee Hyun-jae is a 21-year-old student at Nakwon High School.
He has been held back and has developed a reputation as someone other students and teachers should avoid.
Rather than trying to defend himself against every rumor, Hyun-jae has seemingly become accustomed to being treated as a problem.
Ki-woo’s approach is different.
He is one of the first adults to genuinely ask Hyun-jae about what is happening beneath his behavior.
That attention becomes extremely important to Hyun-jae and gradually develops into an intense emotional attachment.
Kim Jeong-ha – Lee Jeong-chan
Kim Jeong-ha is one of the other important young characters in the series.
He is described as a financially struggling student who takes whatever work he can find and has a strong emotional connection with Park Seong-won.
Nakwon Mansion’s promotional material describes Jeong-ha as a Taekwondo-specialized student who hides his feelings while wanting to remain close to Seong-won.
Park Seong-won – Jung Si-wan
Park Seong-won is presented as a model student and class president.
His relationship with Kim Jeong-ha forms the drama’s secondary romance.
The two come from very different circumstances, but the promotional material suggests that their emotional connection becomes another important part of the series.
Boy, With Caution Cast
| Actor | Character |
|---|---|
| Ryu Se-il | Jang Ki-woo |
| Ha Jeong-hoon | Lee Hyun-jae |
| Lee Jeong-chan | Kim Jeong-ha |
| Jung Si-wan | Park Seong-won |
| Park Hong-joon | Young-moon |
| Bae Yeon-hee | Grandma |
| Yun Su-jin | Hyun-jong’s Mother |
| Lim Soo-hyun | Hyun-jong |
Current production listings identify Ryu Se-il and Ha Jeong-hoon as the principal leads, with Lee Jeong-chan and Jung Si-wan among the supporting cast.
Ryu Se-il as Jang Ki-woo
Ryu Se-il takes the lead role of Jang Ki-woo.
The role is particularly important because Ki-woo is not written as a typical carefree romance protagonist. His character carries the consequences of a damaging rumor and has spent years trying to build a life where he cannot easily be accused of doing something wrong.
Ryu’s background is also connected to theatre. His 2026 role in Boy, With Caution represents his first major leading BL drama role.
Ha Jeong-hoon as Lee Hyun-jae
Ha Jeong-hoon plays Lee Hyun-jae.
Hyun-jae is written as a complicated character rather than simply the stereotypical “troubled student.” His behavior is connected to loneliness, isolation and the way other people have repeatedly treated him.
His growing attachment to Ki-woo becomes one of the central emotional conflicts of the drama.
The role also marks an important screen project for Ha Jeong-hoon, who takes one of the two main roles in the series.
Director and Production
Boy, With Caution is written and directed by Lee Son-eum and produced by Nakwon Mansion.
The project is being distributed through Heavenly, the Korean platform known for its BL-focused programming.
Nakwon Mansion’s official production information lists Lee Son-eum as both writer and director and identifies Heavenly as the investment/distribution partner.
The project also comes from the team associated with Grey Shelter, another BL project from Nakwon Mansion.
Boy, With Caution Release Date
Boy, With Caution premieres on September 30, 2026.
Heavenly’s promotional material has announced the first release for September 30 at 7:00 PM KST, although some international listings display the release time differently depending on timezone conversion.
The drama is scheduled to release on Wednesdays.
Release Schedule
| Detail | Information |
|---|---|
| Premiere | September 30, 2026 |
| Day | Wednesday |
| Platform | Heavenly |
| Time announced by Heavenly | 7:00 PM KST |
| Episodes | 8 |
| Release pattern | Weekly |
The reported eight-episode schedule runs through November 2026 if the weekly Wednesday schedule remains unchanged.
How Many Episodes Does Boy, With Caution Have?
Boy, With Caution has 8 episodes.
Current listings show a first season of eight episodes, with the first episode scheduled for September 30, 2026. Episode runtimes are reported at roughly 25–30 minutes.
Unlike a traditional 16-episode Korean television drama, this is a compact web-format BL series designed around shorter episodes.
Where to Watch Boy, With Caution
The drama is being released through Heavenly.
The production’s official information identifies Heavenly as the distribution platform, while international listings also show the series through online streaming services in some territories.
Availability and subtitle options can vary by country, so viewers should check their local Heavenly or licensed streaming listing.
Boy, With Caution Genre
The drama combines several genres:
- BL
- Romance
- Drama
- School drama
- Psychological romance
- Forbidden romance
- Emotional drama
The story is less about a simple school crush and more about how past trauma, social judgment and emotional dependence affect the characters.
Why Is the Title “Boy, With Caution”?
The title reflects the central idea of the drama.
Ki-woo has spent years being cautious because of what happened to him in the past.
Then Hyun-jae enters his life like an unexpected disruption.
The promotional material repeatedly describes Hyun-jae as a kind of “disaster” appearing in Ki-woo’s otherwise uneventful life, while the romance is presented as something that cannot simply be avoided despite the characters’ attempts to be careful.
The title therefore works as both a warning and a description of the story’s central relationship.
Is Boy, With Caution a BL Drama?
Yes.
It is a South Korean BL (Boys’ Love) romance drama.
The main storyline follows the emotional relationship between Jang Ki-woo and Lee Hyun-jae, while a second relationship involving Kim Jeong-ha and Park Seong-won adds another romantic storyline.
Is Boy, With Caution Based on a True Story?
No information from the production indicates that Boy, With Caution is based on a true story.
It is a scripted Korean romance drama created by writer-director Lee Son-eum and produced by Nakwon Mansion.
Is Boy, With Caution Based on a Webtoon?
There is currently no official production information identifying the series as an adaptation of a webtoon.
It is presented as an original production from Nakwon Mansion and Heavenly.
Boy, With Caution Story Themes
Several themes run through the drama:
Judgment and Reputation
Both leads are affected by other people’s opinions.
Ki-woo tries to avoid judgment after a past rumor damaged his career, while Hyun-jae has almost stopped expecting people to understand him.
Loneliness
Both characters are isolated in different ways.
Ki-woo appears to have a stable adult life, but underneath that stability is a person who has deliberately suppressed much of himself.
Hyun-jae, meanwhile, has become used to being treated as someone who does not belong.
Boundaries
The teacher-student relationship is one of the most important complications in the story.
The series explores what happens when emotional attachment begins to challenge boundaries that the characters are expected to maintain.
Anonymous Identity
The “Anyone” chat application gives Ki-woo and Hyun-jae a private space where they can speak more openly.
That creates a contrast between their online relationship and their real-life interactions.
Boy, With Caution Episode Guide
Because the series has not premiered at the time of writing, a complete official episode-title list and detailed episode summaries should not be invented.
The currently announced structure is:
| Episode | Release |
|---|---|
| Episode 1 | September 30, 2026 |
| Episode 2 | October 7, 2026 |
| Episode 3 | October 14, 2026 |
| Episode 4 | October 21, 2026 |
| Episode 5 | October 28, 2026 |
| Episode 6 | November 4, 2026 |
| Episode 7 | November 11, 2026 |
| Episode 8 | November 18, 2026 |
This is based on the currently listed weekly Wednesday schedule and the reported eight-episode order; release dates can change if Heavenly revises the schedule.
Boy, With Caution Trailer
Promotional character teasers have introduced both Jang Ki-woo and Lee Hyun-jae before the premiere.
The teasers emphasize the unusual relationship between the two characters, Ki-woo’s attempts to maintain boundaries and Hyun-jae’s growing desire for the attention he receives from his teacher.
The promotional material also introduces the secondary relationship between Kim Jeong-ha and Park Seong-won.
Boy, With Caution vs. Typical School K-Dramas
| Element | Boy, With Caution |
|---|---|
| Setting | High school |
| Main romance | Teacher and adult student |
| Main genre | BL romance |
| Central conflict | Emotional attachment and boundaries |
| Main characters | Jang Ki-woo & Lee Hyun-jae |
| Secondary couple | Kim Jeong-ha & Park Seong-won |
| Episode count | 8 |
| Format | Short-form web drama |
| Platform | Heavenly |
| Release | Weekly Wednesdays |
What separates the series from a straightforward school romance is the history surrounding Ki-woo and the professional boundary between him and Hyun-jae.
Boy, With Caution Ending
Since the series premieres on September 30, 2026, its ending should not be spoiled or described as fact before the episodes have actually been released.
The official promotional material establishes the central conflict but does not reveal how Ki-woo and Hyun-jae’s relationship ultimately develops.
The eight-episode structure gives the drama a relatively compact format, meaning the relationship and its consequences are expected to develop over a much shorter period than in a traditional 16-episode K-drama.
Frequently Asked Questions
What is Boy, With Caution?
Boy, With Caution is a 2026 South Korean BL romance drama about temporary teacher Jang Ki-woo and 21-year-old student Lee Hyun-jae.
When does Boy, With Caution premiere?
The series premieres on September 30, 2026. Heavenly has announced its first release for the evening in Korea.
Where can I watch Boy, With Caution?
The drama is being released on Heavenly.
How many episodes does Boy, With Caution have?
The first season has 8 episodes.
Who plays Jang Ki-woo?
Ryu Se-il plays Jang Ki-woo.
Who plays Lee Hyun-jae?
Ha Jeong-hoon plays Lee Hyun-jae.
Who directed Boy, With Caution?
The drama was written and directed by Lee Son-eum.
What is the Korean title of Boy, With Caution?
The Korean title is 소년, 주의.
Is Boy, With Caution a BL?
Yes. It is a Korean BL romance drama.
Is Boy, With Caution a remake?
There is currently no official indication that it is a remake. It is presented as a Nakwon Mansion original production.
Is Boy, With Caution based on a true story?
No. It is a scripted fictional drama.
Final Thoughts
Boy, With Caution takes a familiar Korean school setting and places it inside a much more complicated emotional story. Instead of focusing only on romance, the drama builds its premise around reputation, loneliness, past rumors and the difficult boundaries surrounding its central teacher-student relationship.
With Ryu Se-il as Jang Ki-woo and Ha Jeong-hoon as Lee Hyun-jae, the series is set to premiere on Heavenly on September 30, 2026, with eight episodes planned.
The anonymous “Anyone” chat storyline adds another layer to the relationship, allowing the characters to become emotionally close before they can fully acknowledge what is happening in their real lives.