The King's Affection is a South Korean historical drama-romance of 20 hour-long episodes.

Royal twins are born, which is a sign of bad luck, and so the girl twin is ordered killed but Crown Princess Han (Han Chae-ah) fakes the girl's death and sends her to an orphanage. A dozen years later their father is now King Hyejong (Lee Pil-mo) and a young Dam-i (Choi Myung-bin) enters the court as a new royal maid. Crown Prince Lee Hwi discovers his lookalike and instead of thinking "this is weird" sees this as an opportunity to sneak out of the Royal Palace on excursions disguised as Dam-i while she takes his place doing boring things like sitting all day and studying.

It is during this time that Dam-i meets a young Jung Ji-woon (Go Woo-rim) and they start falling in love. Unfortunately Lord Sangheon (Yoon Je-moon), Queen Han's grandfather and a powerful lord at court who ordered baby Dam-i's death, hears about the suspicious lookalike and orders his lieutenant Inspector Jung Seok-jo (Bae Soo-bin) — and Jung Ji-woon's father — to eliminate the new maid just in case. Jung Seok-jo succeeds (and in the process kills a witness maid in front of Jung Ji-woon which leads to their estrangement) but he actually murdered Crown Prince Lee Hwi dressed up as a maid. Queen Han realizes the truth and convinces Dam-i that the only way to survive is to take Crown Prince Lee Hwi's place, which she does.

Another dozen or so years later Crown Prince Lee Hwi (Park Eun-bin, lead in Extraordinary Attorney Woo) is well established — with his two advisors Court Lady Kim (Baek Hyun-joo) and Eunuch Hong (Ko Kyu-pil) as the only two people who know his secret, though later on we find out other people knew but never revealed it to the Crown Prince — but in need of a new tutor because the Crown Prince is a terror to his teachers (in order they don't get close enough to discover his secret). Enter an adult Jung Seok-jo (Rowoon, male lead in Destined With You), a physician who studied in Ming (China) and has recently returned. He is blackmailed into taking the job so that Lord Sangheon has a spy in the Crown Prince's entourage.

Crown Prince Lee Hwi recognizes Jung Seok-jo but not vice versa. All his attempts to get Jung Seok-jo to resign fail and so he remains a tutor and as time goes on Jung Seok-jo starts to have feelings for the effeminate Crown Prince, and eventually vice versa. Their attraction causes ripples that threaten to reveal the Crown Prince's secret (though naturally most observers think it's a homosexual attraction)…

The King's Affection is a fairly large production with lots of locations and people and good period costumes, though also being an idealized picture not dirty and dark. The court intrigue is interesting and Park Eun-bin is very good playing a very subdued character.

I feel that the second half is not as good. I started getting annoyed with Jung Ji-woon who is vey bad at OPSEC and continually lets people notice how he acts around the Crown Prince. Also he is given jobs like sneaking into places and he usually gets caught.

At twenty episodes it does seem to run longer than I'd like. Once people start learning the secret it "speeds up" without actually getting faster. The last two or three episodes is Lord Sangheon and his private army trying to usurp the throne so there's lots of combat and one useless death. The climax is well done and yet has a plot hole as to how Crown Prince Lee Hwi survives. But at least there's a happy ending for all characters.

Overall still was entertaining and maybe had too high expectations.