A Good Day to Be a Dog - Season 1

Hae Na has a crush on one of the male teachers at her school. After a few drinks at a get-together with the teachers, she discloses her feelings to him. However, after she kisses him, she realizes it's Seo Won, the man she can never get close to.

Hae Na begs Seo Won for another chance to go on a date with Bo Gyeom and him as a group to lift the curse. Therefore, Hae Na, Seo Won, Bo Gyeom, and Chae A end up going on a double date to play a room escape game. Seo Won tries to leave for the day, but Hae Na has to stall time until midnight.

Hae Na finds out that Seo Won is afraid of dogs. It complicates things as she has to get a kiss from him while she's changed to a dog. The vice principal brings his dog to work, making Seo Won panic. Hae Na secretly helps Seo Won so that no one finds out about his secret fear of dogs. Meanwhile, Yul witnesses Hae Na transforming into a dog.

Hae Na decides to ask Yul's help and let her into his place while Seo Won is asleep. She kisses him while she's in her dog form, but the curse doesn't get lifted. Later, Hae Na finds out that Seo Won has to be conscious when she kisses him for her curse to be lifted. To do that, she decides to help Seo Won overcome his fear of dogs first.

Seo Won witnesses Ji Won getting bullied by her friends. To secure the evidence of bullying, Hae Na steals the bully's phone while she's transformed into a dog. An anti-bullying committee meeting is held to punish the bully, Jae Hee. To take revenge, Jae Hee decides to falsely accuse Seo Won of sexually harassing her.

A new student, Ji A, transfers to Garam High School, and she turns out to be a shaman. She notices a different energy around Hae Na and Bo Gyeom. Hae Na fails to kiss Seo Won, so she has to seek her chance during the school trip. Meanwhile, some of the students seek out at night, so Hae Na ends up going outside to look for them, risking herself to be exposed.

Yu Na's ex-boyfriend posts Hae Na's secret online. Eun Hwan, who used to bully Seo Won in high school, sees the post and covers the story. Hae Na's mom finds out about her transformation and demands to know who Hae Na's boyfriend is. Hae Na decides to tell the truth to Seo Won and asks for his help.

Kang Eun Hwan blackmails Hae Na, saying he'd expose her secret unless she gives him all her savings. Upon hearing what Eun Hwan did, Hae Na's parents invade his place and find the recordings and photos he took of Hae Na. After seeing what Kang Eun Hwan posted online, Seo Won goes to see him, but he gets tied up instead.

Hae Na and Seo Won start dating officially, but they can't show it at school because of the recent PDA incident between the teachers at a neighbouring school. Although Hae Na and Seo Won try to be subtle at school, a few people notice a romantic vibe between them. Meanwhile, Ji A does a card reading for Bo Gyeom and finds out who he truly is.

The mountain spirit saves Lady Han who was being chased by government officers. During the chase, the baby in Lady Han's womb dies, leaving her in despair. Mak Soon, Lady Han's servant, stays by her side and looks after her. The mountain spirit and Lady Han grow closer as they spend more time together. One day, the mountain spirit senses swordsmen in his mountain searching for Lady Han.

Hae Na's uncle, Dong Chul, comes back to his human form. Hae Na's family finds it strange that his curse got lifted when he hadn't gotten a kiss. Bo Gyeom reveals himself to Hae Na and tells her that he is the one who put the curse on her family. Then he goes on to tell her that he'll lift the curse only if she gives up her love for Seo Won.

Instead of Seo Won's memories, Hae Na's memories of him get erased, making Seo Won despair. Seo Won does his best to win Hae Na's heart again, but it doesn't go as well as he expected. However, Seo Won finds out that Ji A still has memories of him and Hae Na dating. Meanwhile, Ji A visits the mountain where she died in her past life, which upsets Bo Gyeom.

Hae Na keeps getting reminded of the memories she had with Seo Won. After Seo Won kisses her, Hae Na becomes sure that she and Seo Won share certain memories. The mountain spirit finally realizes what happened to Cho Young and that he was mistaken all this time. He decides to return the memories to Hae Na.

After finding out everything about the curse and their past, Hae Na and Seo Won realize how they feel about each other. One year has passed, and Seo Won's birthday is only ten days ahead. Hae Na wants to give him a present that is unexpected but meaningful. She prepares a special present and plans to give it to Seo Won at the school festival. However, an uninvited guest appears at the school.