Warning: Major spoilers for all 10 episodes of Netflix’s Mousetrap (들쥐) follow.
If you finished Mousetrap and immediately thought, “Wait — were the clues there all along?”, the answer is yes.
The finale reveals that Yu-min is behind the present-day theft of Je Moon-jae’s identity. But that is only half of the twist.
Moon-jae, the man we spent most of the series treating as the victim, had already taken Yu-min’s writing and built part of his own identity and career around something that was never truly his.
Once you know the ending, several earlier details suddenly look very different.
Here are 7 clues that make more sense after the Mousetrap ending.
1. Moon-jae’s identity starts collapsing before he understands why
At first, the premise seems simple.
Moon-jae discovers that another person has his face, his name and access to his life.
Naturally, we assume Moon-jae is the original and the other man is the impostor.
But Mousetrap deliberately makes us accept Moon-jae’s version of himself before proving that his own identity was already built on appropriation.
The first trick wasn’t simply hiding the Rat.
It was making us trust the supposed victim.
2. Moon-jae is strangely disconnected from his own past
As the mystery develops, Moon-jae’s past becomes increasingly important.
The finale eventually reveals why.
Yu-min isn’t a random stranger who selected a successful novelist to impersonate.
Their histories are connected.
Moon-jae had taken Yu-min’s writing and used it in building his career, turning the present-day identity theft into a deliberate mirror of what happened years earlier.
Yu-min doesn’t merely want Moon-jae’s money.
He wants him to experience what it feels like when someone else takes ownership of your life.
3. The real mystery was never just “Who has Moon-jae’s face?”
This is one of the smartest pieces of misdirection in the drama.
For much of Mousetrap, we ask:
Which man is the real Je Moon-jae?
But the finale changes the question to something much more uncomfortable:
How much of Moon-jae’s life was actually his to begin with?
His face and legal name may belong to him.
But his reputation as a writer is tied to work taken from Yu-min.
That is why the identity theme works beyond the literal doppelgänger mystery.
4. Yu-min’s revenge copies Moon-jae’s original crime
Yu-min could have exposed Moon-jae immediately.
Instead, his revenge is far more personal.
He takes Moon-jae’s identity.
That structure is the clue.
Moon-jae took Yu-min’s writing and benefited from another man’s talent.
Years later, Yu-min takes the identity Moon-jae constructed from that success.
The punishment is designed to resemble the original wrongdoing.
You took my life. Now watch me take yours.
The finale therefore makes victim and perpetrator much harder to separate neatly.
5. The biggest clue comes after Moon-jae gets his identity back
This may actually be the most important clue in the entire drama.
Moon-jae survives.
He returns home.
His legal identity is effectively his again.
So the identity-theft thriller should be over.
Except Moon-jae now faces something much worse:
he has to write.
Yu-min leaves behind material connected to The Rat Vol. 2, and Moon-jae tries to produce his own version.
He struggles to do it.
The scene brutally exposes the weakness underneath the identity he has spent years protecting: the successful novelist may have reclaimed his name, but he cannot simply reclaim the talent on which that identity depended.
6. The title “Mousetrap” has been pointing at two Rats
For most of the series, Yu-min appears to be the Rat.
And literally, he is the man stealing Moon-jae’s identity in the present.
But symbolically, the ending turns the label back toward Moon-jae.
Moon-jae took another person’s writing and incorporated it into his own success.
So the finale leaves us with two different kinds of theft:
Yu-min steals Moon-jae’s identity.
Moon-jae had already stolen pieces of Yu-min’s life.
That is why asking “Who is the Rat?” has no completely comfortable answer.
7. The final door scene proves Moon-jae never really escaped
The ending gives Moon-jae almost everything he thought he wanted.
His name.
His home.
His life.
And then someone pounds on his door.
Seung-gyu has returned because of the unresolved money problem, while Moon-jae sees Yu-min when he looks outside.
The scene does not clearly establish that Yu-min physically survived. A strong reading is that Yu-min has become part of Moon-jae’s guilt and paranoia.
And that is the real trap.
Moon-jae can recover his legal identity.
He can remove the man who stole his face.
But he cannot return to believing the story he once told himself about who he was.
The Mousetrap Twist Was Hiding in Plain Sight
Mousetrap initially looks like a thriller about a man desperately trying to prove:
“I am the real Je Moon-jae.”
By the finale, that question almost feels irrelevant.
The more interesting question becomes:
What makes an identity truly yours?
Your face?
Your legal name?
Your memories?
Your talent?
Or the life you actually created yourself?
Yu-min steals Moon-jae’s identity in the most literal way possible.
But Moon-jae’s past makes the audience realize that identity theft began long before another man appeared wearing his face.
That is why the ending works so well on a second look.
The Rat wasn’t simply hiding from Moon-jae.
Moon-jae was living inside the trap all along.
The seven clues hidden throughout Mousetrap reveal how carefully the drama prepares viewers for its final twist. Yet the biggest clue may be hiding in the title itself. Explore what Mousetrap really means and who the mouse is at the end to discover how the story’s central metaphor gives these clues an even deeper meaning.



