Warning: Major spoilers for the ending of Netflix’s Mousetrap (들쥐).
If you finished Mousetrap and immediately wondered, “Is Yu-min really dead?”, you are not alone.
The finale appears to give us a clear answer at first.
Seo Yu-min falls into the sea after his violent confrontation with Je Moon-jae.
But then Mousetrap does something important.
It never gives us a body.
And before the credits roll, Yu-min appears again.
So is he actually alive?
Or is Moon-jae simply seeing the man he can no longer escape?
The most accurate answer is:
Yu-min is presumed dead, but Mousetrap deliberately leaves his final fate ambiguous.
And that ambiguity is essential to understanding the ending.
What Happens to Yu-min in the Finale?
Moon-jae eventually tracks Yu-min to the ship heading toward Jeju.
The location matters because it connects the present confrontation with the past that destroyed Moon-jae, Yu-min and Min-young.
There, Moon-jae finally learns the full truth about Yu-min’s revenge.
Yu-min may have stolen Moon-jae’s identity in the present.
But years earlier, Moon-jae had already taken something arguably even more important from Yu-min.
His writing.
His opportunity.
And eventually, the future Yu-min believed should have been his.
Their confrontation becomes violent.
Moon-jae ultimately stabs Yu-min and sends him through a broken window into the sea.
Yu-min disappears beneath the water.
On the surface, that looks like his death.
But the drama never actually confirms it.
Is Yu-min’s Body Ever Found?
No.
This is the most important detail behind the question.
The finale never shows Yu-min’s body being recovered.
That means viewers never receive definitive visual confirmation that he died.
In most thrillers, this is immediately suspicious.
A character falls into the ocean.
There is no body.
Then that character appears again before the story ends.
Mousetrap clearly wants us to question what we have just seen.
However, that does not automatically mean Yu-min survived.
The final scene makes the answer much more complicated.
Why Does Moon-jae See Yu-min Again?
After returning to his life, Moon-jae should theoretically have won.
The man who stole his identity is gone.
He has reclaimed his home.
He has reclaimed his name.
He has survived.
But Moon-jae does not look like a man who has won anything.
Instead, his life begins to collapse from the inside.
Yu-min has left behind an unfinished manuscript connected to The Rat.
The manuscript threatens to expose the truth about Moon-jae’s past.
More importantly, Moon-jae now has to confront something he spent years avoiding:
How much of “Je Moon-jae” actually belongs to him?
Then Yu-min appears again outside.
That creates two possible interpretations.
Theory 1: Yu-min Survived
The first possibility is the simplest.
Yu-min may actually be alive.
He falls into the sea, but his body is never recovered.
The series has already established that Yu-min is exceptionally good at disappearing.
He previously manipulated identities, faked his own death and returned in another form.
So surviving another apparent death would fit the character.
If the Yu-min we see near the end is physically real, then his revenge may not be finished.
His warning to Moon-jae before falling into the sea would then become extremely literal:
Moon-jae believed he had finally eliminated the Rat.
But the Rat survived.
There is, however, a problem with this interpretation.
The drama never gives us independent confirmation that anyone other than Moon-jae sees Yu-min.
That opens the door to a much darker explanation.
Theory 2: Yu-min Is a Hallucination
This is arguably the stronger interpretation.
Yu-min may be dead.
What Moon-jae sees could instead be a manifestation of his guilt, fear and deteriorating psychological state.
By the finale, Moon-jae has recovered his identity legally and socially.
Psychologically, however, he has lost control of it.
He now knows the successful writer called Je Moon-jae was built partly on another person’s work.
Killing Yu-min cannot erase that truth.
So even if Yu-min’s body is at the bottom of the sea, Yu-min continues to exist inside Moon-jae’s mind.
That makes his final appearance much more meaningful than a simple “he survived” twist.
Moon-jae can kill the man.
He cannot kill what the man knows about him.
Why Moon-jae Can’t Write After Yu-min Disappears
One of the smartest details in the finale comes after Moon-jae returns home.
He sits down to write.
And nothing comes.
This echoes an earlier image of Moon-jae staring at a blank screen.
The problem is no longer writer’s block in the ordinary sense.
The finale forces Moon-jae to confront the possibility that the identity he built as a brilliant novelist was never entirely his own.
Yu-min’s writing helped create the author the world knows as Je Moon-jae.
Now Yu-min is gone.
And Moon-jae is left alone with the blank page.
That is why Yu-min does not need to physically survive in order to defeat him.
His revenge has already worked.
So Who Really Wins: Moon-jae or Yu-min?
Physically, Moon-jae wins.
He survives.
He returns home.
He keeps his identity.
Yu-min disappears into the sea.
But psychologically?
Yu-min wins.
Moon-jae wanted his life back.
Instead, he gets that life back only to discover that he can no longer believe in it.
His career is contaminated by what he stole.
His past can still be exposed.
He cannot write.
And the man he thought he killed continues to appear before him.
That is a much crueler punishment than simply losing his identity.
What Does Yu-min’s Final Appearance Really Mean?
Whether Yu-min is physically alive may actually be the wrong question.
The deeper point is that Moon-jae can never completely get rid of Yu-min.
At the beginning of Mousetrap, Moon-jae believes another man has stolen his identity.
By the end, he discovers that his own identity was already built through theft, deception and borrowed talent.
Yu-min therefore becomes more than the villain chasing him.
He becomes evidence of everything Moon-jae wants to forget.
That is why seeing Yu-min again matters.
If Yu-min survived, Moon-jae remains physically hunted.
If Yu-min died, Moon-jae remains psychologically hunted.
Either way, Moon-jae cannot escape him.
Is Yu-min Really Dead? Final Answer
The drama does not definitively confirm Yu-min’s death.
Here is what we actually know:
- Moon-jae and Yu-min fight aboard the ship.
- Yu-min falls into the sea.
- His body is not shown being recovered.
- Moon-jae later sees Yu-min again.
- The series does not establish whether that appearance is real or psychological.
So the safest answer is:
Yu-min is presumed dead, but his fate is intentionally left ambiguous.
Personally, the psychological interpretation fits the ending best.
Yu-min does not need to survive.
His real victory is forcing Moon-jae to understand that recovering his name cannot restore the person he believed himself to be.
Moon-jae gets his identity back.
But by the time he gets it back, he no longer knows whether it was ever truly his.
And that may be the darkest twist in Mousetrap.
More Mousetrap Questions
If the ending left you confused, the biggest questions are all connected:
Who is the real Rat?
Yu-min is responsible for the present-day identity theft, but the finale turns the idea of “the Rat” back onto Moon-jae and his own history of taking what belonged to others.
Why can’t Moon-jae write at the end?
The blank page forces him to confront how much of his literary identity was built on Yu-min’s work.
Who is at Moon-jae’s door in the final scene?
The final visitor shows that even after Yu-min disappears, Moon-jae’s past and debts are still coming for him.
Mousetrap is streaming on Netflix.
Whether Yu-min survived remains one of Mousetrap’s most intriguing unanswered questions. But the uncertainty surrounding his fate also changes how we interpret Moon-jae’s final moments. Explore why Moon-jae becomes the Rat at the end of Mousetrap to see how the final twist connects Yu-min’s mystery to Moon-jae’s identity.