Episode 3 of A Good Day To Be A Dog starts with Hae-na waking up from a dream where she sees all her colleagues at the high school finding out about her secret. In the dream, the colleagues treat Hae-na as a dog which gets her worried. At the same time, Sae-won enters Yul’s room and is shocked to see Hae-na there. He sits the two down and asks if they were up to something questionable the night before. Hae-na asks Yul to keep her turning into a dog a secret.
Together, Hae-na and Yul cook up a lie and tell Sae-won all about the police complaint and how Hae-na saved him from the cops. Hae-na lies that she was extremely drunk the night before and passed out in the cab. She adds that she ended up sleeping in Yul’s bed while he slept on the sofa outside.
The two clarify that Yul ended up inside the bedroom because he was uncomfortable sleeping on the sofa. Sae-won seems to have bought the lie and thanks Hae-na for saving her nephew. Just then, Miss Yoon who was waiting for Sae-won to go on his morning jog, spots him escorting Hae-na outside his apartment complex. She snoops and overhears them talking about a secret. Sae-won asks Hae-na to keep the fact that he’s Yul’s uncle a secret.
Sae-won asks Hae-na to cut down on her drinking as she has been getting into trouble lately for drinking. Hae-na takes her leave and goes to Woo-taek’s pet clinic. She tells the truth about the night before and Yu-na scolds her sister for being reckless with the secret. Meanwhile, Sae-won prepares breakfast for Yul before school.
Yul asks Sae-won to let him adopt a pet dog and acts like one to make his case. Sae-won promises to consider his request and asks him to have breakfast as they are late for school. Sae-won notices a pet shop on his way to work but gets worried when the door to the shop opens.
Yu-na drops Hae-na to work and asks her to gift a dog keychain to Sae-won in order to reduce his fear of dogs. She claims that if Sae-won kept the keychain with him, he would get accustomed to the feeling of the furry animal, helping Hae-na easily reverse the curse. Hae-na is sure Sae-won won’t agree to keep the keychain but Yu-na asks her to try.
On her way to work, Bo-kyum spots Hae-na holding the keychain and talks to her about how much he likes dogs. They make their way inside the school and Sae-won watches them from afar. Miss Yoon asks Sae-won to join her for a walk and tells him that he can trust her with a secret. She tells him a secret of her own and asks the Math teacher to tell her a secret. Sae-won is weirded out by the conversation and asks to take Miss Yoon’s leave.
The Vice Principal of the school brings his daughter’s dog, Mandeuk, to work that day and keeps the pet in the staff room. Hae-na, aware of the fact that Sae-won dislikes dogs, tells the Vice Principal that she is allergic to put Mandeuk in a cage. Sae-won observes the conversation from outside and is happy that Hae-na is trying to cage the animal.
The Vice Principal stated that Mandeuk was not used to closed spaces and asked Hae-na to take a pill for her allergies. He asks Sae-won to go bring Mandeuk’s feeding bowl and food from his car. Sae-won is asked to feed the dog as well and he is petrified to do so. He finally sneaks into the staffroom from the back door and fills Mandeuk’s feeding bowl silently.
However, the dog hears his food being dropped in the bowl and chases towards it. With Sae-won’s back to Mandeuk, he is unaware of the fact that the dog is running towards him. Hae-na pushes Sae-won out of Mandeuk’s way and tells him that she is running late for class. Sae-won notices how Hae-na is trying to help save him from coming in contact with Mandeuk.
Later that day, Hae-na asks Yul to keep her secret safe with him and is happy that Yul likes dogs and has promised to help Hae-na. The entire day goes by with Sae-won avoiding entering the staff room as Mandeuk is resting there. He asks Bo-kyum to help him with his books and offers to buy his favourite fondant cake.
That afternoon, Bo-kyum brings Mandeuk outside and the dog runs towards Sae-won but Hae-na manages to throw a toy making Mandeuk go the other way. Sae-won sees Hae-na as his saviour while she acts nonchalantly about his phobia. The female teachers point out that Sae-won was nowhere to be found the entire day.
Hae-na learns that Mandeuk has gone home and tries to alert Sae-won about it. She goes outside his class and pretends to talk to someone on the phone. She tries to tell Sae-won that Mandeuk has left and that the staff room is clear. After his class, Sae-won finally goes to the staffroom for the first time and rests in his chair.
All of a sudden, Hae-na learns that the Vice Principal has come back to the school with his dog. She tries to rush to the staffroom to alert Sae-won but notices that Sae-won has jumped on the table to get away from Mandeuk. She immediately picks up the dog and holds it away from Sae-won.
Hae-na lies to the other teachers and tells them that Sae-won is on the table to fix the sprinkler. Sae-won agrees with Hae-na and states that it would be hilarious for a grown man to be afraid of dogs. Sae-won takes a sigh of relief, thankful for Hae-na for saving him. A flashback shows how Sae-won has fallen for Hae-na ever since she joined Garam High School as a teacher.
Back to the present day, Bo-kyum tells Mandeuk that he did a good job as the Vice Principal takes the pet dog back home after school. He spots Hae-na at the cake shop and calls Sae-won, asking him to buy him the cake he promised. Sae-won shows up at the cake shop and sees that Hae-na is debating on eating her favourite cake. She tells him that she did not want to crave something sweet late in the night but does not specify why.
Sae-won ends up buying all the chocolate cakes to save Hae-na from having the urge to buy them. The two walk back to the bus stop together and talk about the day that went by. Sae-won thanks Hae-na for saving him from Mandeuk all day and Hae-na reveals that she knew he had a fear of dogs and just wanted to help her. She validates his fear and tells him how she had done more embarrassing things in front of Sae-won.
Sae-won is enamoured by Hae-na’s comment. She leaves the dog keychain on his bag and tells him it could be a good way for him to get over his fear. Sae-won gives Hae-na one of the cakes and asks her to eat it during the day instead. At home, Hae-na lets Woo-taek and Yu-na eat the cake as she won’t be able to have any because she is going to turn into a dog. Meanwhile, Sae-won joins Bo-kyum in the woods and shares the cake with him.
Bo-kyum notices the dog keychain and asks Sae-won about it. Sae-won ignores the question and wonders why Bo-kyum lived in the woods instead of living in a house like everyone else. Bo-kyum tells Sae-won that he was waiting to finish a task and was in the woods for that period of time.
The next day, Bo-kyum goes to a shady basement near the school and enters what looks like a hidden room. He opens a chest and holds up a fabric that resembles one that people from the Joseon era wore. Meanwhile, the teachers get invited to their fellow colleagues’ wedding.
The teachers discuss how the wedding was held at a remote location and they would have to take the bus to go there. Song-yi asks Bo-kyum and Hae-na to go to the gift shop to purchase a gift for the wedding on behalf of the teacher. Sae-won overhears the conversation and offers to go instead of Bo-kyum as he has many papers to grade that day.
Sae-won and Hae-na spend some fun time at the mall and end up buying a couple’s night suit as a wedding gift. Hae-na tells Sae-won how she wanted to stop by a pharmacy to buy medicine for the bus trip as she has a few allergies. Sae-won offers to take a car to the wedding location and asks her to join him.
Miss Yoon who is also at the same mall overhears the conversation. She shows up in front of Seo-won and Hae-na, asking them if they’d like to carpool with her and Bo-kyum. Seo-won opts out of carpooling but Miss Yoon forces Hae-na to join them. Seo-won is disappointed that Hae-na didn’t stand up to Miss Yoon.
At the same time, Miss Yoon calls Bo-kyum and tells him all about Seo-won and Hae-na leaving the former’s apartment that day. Bo-kyum finally agrees to join the carpool. The next morning, Hae-na gets dressed for the wedding with Yu-na’s help. Bo-kyum and Miss Yoon wait for Hae-na to show up but Song-yi joins, stating she will be carpooling with them instead of Hae-na.
Just then, Seo-won shows up at the park and tries to lead Hae-na to his car when he spots Miss Yoon. The episode ends with Seo-won holding up his umbrella to hide him and Hae-na from being seen by Miss Yoon.
It was so endearing to see that Seo-won already had feelings for Hae-na right from when she joined the school as a teacher. If the trope this show is going with is “He fell first, she fell harder”, I am all for it. As for Bo-kyum, something about him feels off. It’s as if he wants Seo-won and Hae-na to be around each other and also does not want them to get along.
It is possible that he was the one who cursed Hae-na in the past and is making sure that the curse doesn’t end by forcing her to be around Seo-won who is clearly afraid of dogs.