These episode summaries are generously provided by taeklatte:
Ep 17 (just some key points?) fyi my Chinese isn't that great.
Basically Hu Li suspect Ye Zhao (general)'s cousin for adding some type of drug into the plants (or the plants together creates an ill effect, don't remember that clearly) she gave to Yu Jin (general's husband) but the couple does not seems to realize that. Hu Li had to keep low about it because the general really treasures her cousin and both her husband and herself believe the cousin to be pure and innocent. Hu Li instead told Yu Jin that it would be better to have the plant outside and to not to eat any desserts the cousin made because Yu Jin is recovering from his illness. Hu Li in this episode also tries to predict the cousin's motive, he reasoned that she might hate Yu Jin because he took away Ye Zhao from her so she is plotting against Yu Jin.
When Ye Zhao, Cousin and Yu Jin went out, Yu Jin fell into the water because the cousin shot a concealed needle to his knee. His knee becomes numbed and he fell from the bridge into the water. The Cousin jumped into the water to try to save Yu Jin but they both can't swim. Under the water, the cousin chopped Yu Jin's neck. The general ended up saving both of them but this event happened in front of a large crowd. General later on noticed the bruise on Yu Jin's neck and finds it strange so she also asked him where else did he get hurt and found out that the injury on his knee was caused by a concealed needle. The cousin cries about how she lost her maiden's innocence because she was caught together with Yu Jin in front of a large crowd (imo I think this means that the crowd might think there's something going on with her and Yu Jin).
Ep 18
Ye Zhao and Yu Jin pretends to have a fight over having the cousin become a concubine but it did not fool the cousin. The cousin became rather sad and angry because she knows that despite the spat, even if it was pretend, Ye Zhao will still stay with Yu Jin. The cousin plotted this so that Ye Zhao will separate/divorce Yu Jin. The Cousin wanted Ye Zhao to wake up and see that her husband isn't suited for her. End of this ep, the cousin wanted Ye Zhao to "wake up" so she decides to hang herself.
Ep 19
Ye Zhao managed to get there in time, pass air mouth to mouth to the cousin. Yu Jin's personal servant saw this and reported to Yu Jin, Yu Jin became very jealous and say he'll commit suicide as well. Basically this episode, Ye Zhao is squished in the middle between her fragile attention seeking cousin and her jealous attention seeking husband. Yu Jin wants Ye Zhao to send the cousin back to home. But Ye Zhao is still considering about it. We find out from Hu Li that her cousin is her only cousin, she doesn't have any other cousins. Her family consists of her cousin, her widowed sister in in law with her two sons, her not sane grandfather and her uncle. Hu Li spoke about how some things are easy for one person to obtain but hard for another person, comparing Yu Jin's 10+ cousins and living relatives to Ye Zhao's. Yu Jin from this conversation still wants the cousin to be gone but decides that he'll take whatever decision Ye Zhao makes. We get another scene of where Ye Zhao is lonely due to the lack of family members, where she has a dilemma but doesn't really have anyone by her side to support her. Her mentally ill grandfather keeps telling her to seek advice from her parents. It is rather heartbreaking to see that the people her grandfather suggested her to seek advice from is no longer alive but yet she has to pretend that they are alive in front of her grandfather.
Ep 20-21
After seeking getting advice from her father through a mirage/day dream type of thing where the father said something along the lines of even in war we have to make sacrifices. Ye Zhao decides to send her cousin back home. She explained to her cousin that she fell love at first sight with Yu Jin, she doesn't want to give Yu Jin up and that she owes him alot because when they were little, she caused him to fall into water resulting in his mother locking him up. In some sense, General feels that she owes her cousin because she made her cousin wait for her return despite the fact that she knows that her and her cousin can never be together due to her gender so she feels guilty about that and wants to do the best she can for her cousin. We get more details about the political structure in this drama. General beheaded the Empress's nephew due to the nephew violating the military code of picking on lower ranked soldiers and killing a civilian soldier. Empress complains to the Emperor and asked the Emperor to pardon her nephew but Emperor deny the request since military code was set up by the previous Emperor and the nephew killed someone. Empress vows to remember General's name for revenge. Current favorite consort is the Imperial Consort and not the Empress. Empress is jealous of the Imperial Consort and tries to make things difficult for her. In a spat between the Empress and the Imperial Consort, the Empress injured the Emperor. This action allowed some ministers try to remove the Empress and to replace her with someone else.
Ep 22-24
From ep 22 to 23 the General and Yu Jin doesn't appear much. Some of the officials tries to persuade the Emperor to not replace the Empress but Emperor never really liked the Empress. Some drama in the harem, the Empress Dowager is not really his mother and his real mother dies and his real parentage was revealed after his real mother + Empress Dowager passed away. Before his real mother died, the General had the Emperor and his real mother meet up but the real mother did not reveal who she is because the Empress Dowager asked her not to. Current Empress Dowager is his second mother, so Emperor has a real mom, a mom (Empress Dowager), and a second mom (his father's imperial consort). In ep 24 some of the officials bought up an issue of getting the nobles to all take an exam. If they don't pass the exam, they will lose their job, only nobles between 15 to 25 (I think) have to take this exam. Ye Zhao persuades her husband to study to take this exam and that she believes him. Yu Jin asked her why should he even take this exam, her reply is to prove himself, that he is smart and intelligent and he is a not a wastrel.