Overall I think this drama is decent. It has a nice romantic lead and decent enough story. I thought the FL's character is a more interesting female character than most. Even though she's just a doctor, she's witty enough to get by and smart enough to know some of the things going on around here. More often than not, FL is totally clueless and can't defend herself.

Basic Character Intro:
Tian Qi (FL, originally Shen Zhao Er) is a daughter of an imperial doctor who serve the Ji Manor. Her parent were killed and she's saved by a secretive female doctor (uncommon for female to be doctor). She trained in medicine so she can eventually go back to the Ji manor to find out why her family is killed.
Ji Heng (ML) is the young heir and head of the Ji family. He's a stern and respected head of the Ji family who handle not only the affair of his household but also various power struggle happening within the court. He's tormented by the fact he couldn't save his childhood sweetheart's, Shen Zhao Er (who although was around him a lot, never knew his real identity), parent and not sure what happened to her since he only found her parent's bodies.

Story:
Pretty basic. Tian Qi, posing as a man studying to be a doctor, finally become good enough to be assigned to the imperial court. However she secretly wanted to entered the Ji manor and powerful government official family. So she pulled some string to posed as a doctor to lady who was to be wedded to the young head of the Ji manor. The lady died shortly after Ji Heng came back. Because the emperor's betrothed was randomly killed, he's required to investigate and explain to the king what happened. Tian Qi, seemingly close to the lady was tasked by Ji Heng, who's also very suspicious of Tian Qi, to find out why she died otherwise he'll killed her. So throughout this Ji Heng got to know Tian Qi a little more and started developing feeling for her. Behind the scene, there are multiple parties who were involved revenge/power plot (like 4)...standard stuff. Ji Heng, also had a younger brother, Ji Zheng, who was attracted to the FL and actually found out she's a girl early on. So Ji Zheng is essentially relegated to a second male lead who had less power but at time are more willing to save the FL, who also realize his predicament (of having less power, thus less able to protect one he loves) became bolder and more willing to challenge his brother for authority. (a very standard 2nd ML type). The story is really nothing special but I at least applaud them for have a plot of somewhat but it's not like that plot is great to begin with.

So I'm just highlighting a few points for this drama:
1. No the ML did not find out about her female identity until episode 21-22 (out of 28 episode). Despite a weak attempt by the FL to pretend to be more macho...lol...and literally the ML made the FL dress up as a girl two episodes before but apparently unless he saw her half naked, he's not willing to jump to that conclusion. LOL
2. The revenge plot is weird. Not even much of a spoiler, but one of the biggest villain of a story is the son of a family who was taken out by the Ji family but he not only planted 1 but 2 figures inside the Ji family. These two sacrificed for nothing if you think about it. I mean he's not that great of a villian...even his final attempt at the end of the story came out flat.
3. The reason for why her family was killed was rather weak and a disappointing reveal.
4. One of the major plot point is that fact Ji Heng is tormented by not being able to saved the family of the girl he likes when he was young....who as mentioned before turns out to be the FL. He has constant nightmare and would wake up yelling out "Zhao Er" from time to time. Tian Qi, who is now a resident doctor of the Ji manor, somehow put the Ji Heng at ease at night (cause a sense of comfort he felt with her) so she's ended up spending many night at his residence helping him sleep. You would've thought Tian Qi would eventually hear Ji Heng yelled out her female name or...you know...as a doctor ask her patient find out why he's having nightmare (technically he did breifly mentioned not being to save someone he cared about...but no further inquiry on her part). Nope, in fact, he didn't find out about her Shen Zhao Er identity until after episode 22 (maybe around 24) and she didn't realize he's her little older brother (her childhood nickname for him) until episode 26, I think. Yes most of the reveal happened in the last 6-7 episode of the drama. -_-
5. Yes so if you're impatient about the reveal, just skip to episode 22.
6. There are simply no standout antagonists. It felt like everyone beside those very close to the FL and ML are bad guys. But they don't do much. Perhaps it's better to focus on a really good one instead of having a bunch of mediocre ones.
7. Yea, is a HE but it's really draggy in the middle portion. I feel like things could've been cut down to under 20 episode. Removed a few useless villians. For example, Ji Heng cousins (male and female) are a total waste of space in the drama. They offered absolutely nothing to the story.
8. The 2nd Male Lead honestly didn't do much in the story. They tried to give him something toward the end, especially with that reveal about Ji Heng's mom...which is also weakly developed. Nothing they did with him did any impact at all.

Final Thought:
I think the story had a decent structure but it's poorly develop. In other word, it had potential but in the end came out flat. Do I recommend it? It's not terribly bad, I like both the ML and FL and they have pretty good chemistry from time to time. I thought both the ML and FL are cute from time to time. FL for how she handles situation around her and ML for how FL made him fluster here and there. LOL And I did think the story was interesting at the beginning, though i don't think there's much of a payout at the end :/. Pick it up if the initial few episodes appeal to you but the FF button is your best friend if you want to go through the drama to the end.