Love in Disguise webtoon already has its ending (but the drama keeps changing things)

Love in Disguise premiered on tvN on October 19, 2026, with Yim Si-wan as a chaebol heir suspected of murder and Seol In-ah as the special forces-trained detective who goes undercover as his male secretary. It streams on Prime Video outside Korea and runs 12 episodes through late November.

The story comes from a finished source: Lee A-hyun and Ryu Do-ha's web novel Why Don't You Know It's a Girl? (여자인 걸 왜 모르지?), wrapped up in three volumes and adapted into a 106-chapter Kakao webtoon. The drama has kept the setup and is quietly rearranging almost everything else.

The first week landed well. The premiere drew 5.6% nationwide, and episode 2 dipped to 4.7% while still winning its time slot, per Korean ratings reports. Spoilers for the original ending below.

The setup both versions share

In both, Kang Jae-hee is a former special forces soldier turned police officer, and the assignment is the same: spend three months as Yoon Yi-jun's personal secretary and find out whether he's a killer. A female employee at his family's company has been murdered, and Yi-jun is the suspect.

The original's tagline sums up the joke. Jae-hee knew the job was dangerous, but "the genre is romance, not thriller." Yi-jun confesses he likes her before he even knows her last name.

How the original ends

The web novel's last volume gives the game away in its chapter titles: "Rumor's Truth," "How Did You Know?," "Coming Out," "Downfall" and "Each in Their Place," followed by six epilogues and two extra stories. Readers who finished it describe the ending like this:

• Yi-jun knew: He's the one who figures out early that his secretary is a woman. When threats against him pile up, he moves into Jae-hee's rooftop room, tells her he knows she's a woman, and she tells him she's a cop.
• The case: Yi-jun turns out to have been the only witness to the murder, not the killer, and it left him badly shaken. A missing man named Park Min-hwan turns himself in with evidence, and the real culprit is exposed.
• The heir walks away: Yi-jun voluntarily resigns from his family's company.
• The couple: They get married and have a son, Si-hu, who looks just like his father. One of the extras has Yi-jun at home as a stay-at-home husband backing his detective wife.

Several readers' complaints are the same: the mystery wraps up too easily, and Yi-jun works out that she's a woman too fast. In the book, the case was never the main event.

The original's title asks why he doesn't know she's a woman. The answer in the book is that he does. He just doesn't say so until he's living in her rooftop room.

What the drama is changing

The drama keeps the names and the premise, but the differences are already visible, Wikitree reported when it premiered:

• Whose story it is: The original is a romance told around the heroine. The drama recenters it on Yi-jun, the third-generation heir named as a murder suspect.
• The disguise: In the novel, Jae-hee's height and manner make people assume she's a man. In the drama, she applies for the job deliberately disguised as a male secretary.
• The company: Samgang Group in the book becomes Taegang Group on screen.

The tone shifts with it. The drama sells itself as a tense romance-thriller, with falling chandeliers and weedkiller in Yi-jun's milk in the early episodes, which puts a lot more weight on the case than the book ever did.

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Where that leaves the ending

The biggest change is the one the drama hasn't played yet. The book's romance works because Yi-jun is in on the joke early, while the drama's premise depends on keeping him in the dark. In episode 5, per Soompi, the two share an accidental kiss that Jae-hee doesn't even remember, and Yi-jun is left flustered by it.

About halfway through, the drama can still land where the book does, with a married couple, a resignation letter and a kid who looks like his dad. It's just taking the long way there. The book spent its plot on the romance and wrapped up the murder fast, and the drama, by making the case its spine, has signed up for the part the original's readers said it skimped on.

Previously we wrote: When the Phone Rings ending explained: who the kidnapper really is