Warning: Major spoilers for Netflix’s Mousetrap (들쥐).
At the end of Mousetrap, Je Moon-jae finally gets his life back.
Yu-min is gone.
Moon-jae returns home.
His name, his identity and his place in the world appear to belong to him again.
Then he sits down in front of his computer.
And he cannot write.
It looks like a simple case of writer’s block.
It isn’t.
Moon-jae’s blank page is one of the most important images in the entire ending of Mousetrap.
Because after everything that happens, Moon-jae is forced to confront a terrifying question:
Was the famous writer “Je Moon-jae” ever really his own creation?
The short answer is that Moon-jae cannot write because Yu-min’s revenge has destroyed the identity on which his career was built.
Here’s why.
What Happens to Moon-jae at the End of Mousetrap?
For most of Mousetrap, Moon-jae’s biggest fear is losing his identity.
Another man enters his life.
His home is taken.
His relationships are threatened.
Even the name “Je Moon-jae” seems capable of being stolen from him.
So Moon-jae spends much of the story fighting to reclaim what he believes belongs to him.
Eventually, he confronts Seo Yu-min aboard the ship.
Their violent confrontation ends with Yu-min falling into the sea.
Moon-jae survives.
At first glance, that should be the end of his nightmare.
But Mousetrap deliberately refuses to give Moon-jae a triumphant ending.
He returns to the life he fought so desperately to recover.
Then he tries to do the one thing that defines Je Moon-jae more than almost anything else.
He tries to write.
Nothing comes.
Is Moon-jae Just Suffering From Writer’s Block?
Not in the ordinary sense.
Writers can obviously struggle to produce new work because of stress, exhaustion or trauma.
Moon-jae has experienced all three.
But the drama has spent too much time connecting Moon-jae, Yu-min and writing for the final blank page to be accidental.
The problem is not simply:
“Moon-jae has no idea what to write next.”
The real problem is:
“Moon-jae no longer knows whether he deserves to call himself the writer he became.”
That difference is crucial.
Moon-jae’s Success Was Never Entirely His Own
The finale changes how we understand Moon-jae’s career.
For years, Moon-jae has lived as a successful writer.
That career is a huge part of his identity.
But his past with Yu-min forces us to reconsider where that success began.
Moon-jae benefited from writing and opportunities that were connected to Yu-min.
What looked like Moon-jae’s talent and achievement becomes morally contaminated once the truth about their past is revealed.
That is why Yu-min’s revenge is so effective.
Yu-min does not merely try to steal Moon-jae’s current identity.
He attacks the foundation beneath it.
And once that foundation is exposed, Moon-jae can no longer look at himself in the same way.
Why the Blank Screen Matters
The blank screen is not just an empty document.
It represents Moon-jae himself.
Until this point, Moon-jae has been obsessed with proving:
“I am Je Moon-jae.”
But sitting in front of the empty page forces him to answer a different question:
“Who is Je Moon-jae without Yu-min?”
That question is much harder.
A name can be legally restored.
A house can be reclaimed.
A stolen identity can be recovered.
But creative legitimacy cannot be restored so easily.
Moon-jae now knows that the story he told himself about his own success was incomplete.
And once he knows that, writing becomes almost impossible.
Why Yu-min Doesn’t Need to Be Alive to Defeat Moon-jae
This is what makes the ending particularly cruel.
Yu-min may be dead.
He may have survived.
The drama intentionally leaves room for both interpretations.
But for this part of the ending, it almost does not matter.
Yu-min has already entered Moon-jae’s mind.
Moon-jae cannot sit at his computer without confronting what Yu-min represents.
Every new sentence raises another uncomfortable question.
Is this really mine?
Was I ever as talented as I believed?
Would I have become this successful without what happened to Yu-min?
Am I the victim of identity theft—or did I build my own identity by taking something from someone else first?
Yu-min’s revenge therefore continues even in his absence.
The Biggest Irony of Mousetrap’s Ending
The entire story begins with Moon-jae terrified that someone is taking his identity.
That makes us instinctively sympathize with him.
Someone else living as you is horrifying.
But Mousetrap gradually turns that idea upside down.
By the finale, the question is no longer only:
Who stole Moon-jae’s identity?
It becomes:
How was Moon-jae’s identity created in the first place?
That is the trap.
Moon-jae spends the story trying to expose the fake version of himself.
In doing so, he is forced to expose the uncomfortable truth behind the real version too.
Why Writing Is the Perfect Punishment for Moon-jae
Yu-min could have simply destroyed Moon-jae’s career.
He could have exposed him publicly.
He could have taken away his money, reputation or freedom.
But Mousetrap chooses something more personal.
Moon-jae keeps his life.
And then he loses confidence in the thing that made that life meaningful.
For a writer, the blank page becomes a form of punishment.
Nobody has to stop Moon-jae from writing.
Nobody has to confiscate his computer.
Nobody has to cancel his books.
Moon-jae stops himself.
That is why the ending is psychologically stronger than a simple revenge story.
Yu-min does not need to destroy Moon-jae from the outside.
He makes Moon-jae destroy his certainty from within.
Is Moon-jae Actually a Talented Writer?
This is another question the ending deliberately complicates.
The finale does not necessarily prove that Moon-jae has no talent at all.
That interpretation would be too simple.
Moon-jae has lived and worked as a writer for years.
The more interesting issue is that he can no longer separate his genuine ability from the morally compromised beginning of his career.
Perhaps some of his later success really was his own.
Perhaps he developed into a legitimate writer.
But that does not erase the past.
Moon-jae himself can no longer tell where Yu-min ends and Je Moon-jae begins.
And once that boundary disappears, so does his confidence.
The Blank Page Mirrors Moon-jae’s Identity Crisis
There is another way to understand the scene.
A blank page contains nothing.
It has no story.
No identity.
No meaning until someone creates one.
That is exactly where Moon-jae finds himself at the end.
The identity he spent years living inside has been stripped down.
The famous novelist.
The successful man.
The victim whose life was stolen.
All those labels have become unstable.
Moon-jae has his name back.
But psychologically, he is almost a blank page himself.
Now he has to decide whether he can create a new version of himself without stealing from the past.
The drama ends before giving us that answer.
Did Yu-min Ultimately Win?
In one sense, yes.
Moon-jae survives their confrontation.
He returns home.
So physically, Moon-jae appears to win.
But Yu-min’s real objective goes deeper than physically replacing him.
He wants Moon-jae to understand what it feels like to have your identity taken away.
By the end, Moon-jae understands that feeling completely.
More importantly, Yu-min forces him to question whether the identity he is fighting to recover was morally his in the first place.
That is why Moon-jae sitting helplessly before a blank screen may be Yu-min’s greatest victory.
Why Can’t Moon-jae Write? Final Answer
Moon-jae cannot write at the end of Mousetrap because his confrontation with Yu-min destroys the psychological foundation of his identity as a writer.
It is more than ordinary writer’s block.
The blank page represents:
- Moon-jae’s guilt over his past with Yu-min.
- His uncertainty about how much of his success was truly his.
- The collapse of the identity he spent the entire drama trying to reclaim.
- Yu-min’s continuing psychological control over him.
- Moon-jae’s fear that without Yu-min, there may be nothing original left to write.
That is the final irony.
Moon-jae spends Mousetrap desperately trying to get his identity back.
He succeeds.
But when he finally gets it back, he can no longer believe in it.
The man called Je Moon-jae survives.
The writer called Je Moon-jae may not.
And that blank page is how Mousetrap shows us the difference.
More Questions About the Mousetrap Ending
Is Yu-min Really Dead?
Yu-min falls into the sea, but the drama does not give viewers definitive confirmation of his death. His later appearance can be interpreted either as survival or as a manifestation of Moon-jae’s guilt and fear.
Why Does Moon-jae See Yu-min Again?
If Yu-min is dead, his appearance suggests that Moon-jae can no longer psychologically escape him. Yu-min has become a permanent reminder of the truth behind Moon-jae’s identity.
Who Really Is “The Rat”?
The title becomes increasingly complicated by the finale. Yu-min may be the literal identity thief in the present, but the story also forces viewers to reconsider Moon-jae’s own actions in the past.
That reversal is what makes Mousetrap much more than a conventional identity-theft thriller.
Moon-jae’s inability to write is not simply a creative block. It raises a deeper question about whether reclaiming his name means he has truly recovered his identity. The finale takes that uncertainty even further. Explore why Moon-jae becomes the Rat at the end of Mousetrap to see how the blank page connects to the story’s final reversal.