Sa-ra is a hot-shot divorce lawyer and the daughter-in-law of the owner of Korea’s top law firm, Chayul. Through the case she took to be recognized as part of the Chayul family, she meets Gi-jun, her former lover from nine years ago. Gi-jun, who can’t stand seeing bad guys win, gives a piece of advice to Sa-ra, but she gets schemed by her husband, Yul-seong, and her mother-in-law. She gets divorced in disguise and even ends up in prison. Sa-ra becomes an ex-convict from a lawyer overnight.

After Sa-ra gets released from prison, she returns to work as a divorce fixer and the team leader of Solution. One day, she takes the divorce case of a best-seller writer and Korea’s top anchor. The opposing counsel turns out to be Chayul. Sa-ra begins her solution service against her ex-husband, Yul-seong. Meanwhile, Prosecutor Dong Gi-jun focuses his attention on the Na Yu-mi suicide case. As he digs into it, he becomes aware that Yul-seong is deeply involved in the case. What’s the truth behind this case?

Solution becomes whole when Gi Jun, an unconventional lawyer, joins the team. Their fearless solution and punishment for justice begin in earnest. They can't just sit back and let Jang Jae Gook go on with his one-man show. With Sa Ra's special solution, they punish the vicious husband. Their solution for this case is for the victims to join hands. Meanwhile, an unexpected client visits Solution, which astonishes Sa Ra.

Ji In is facing the same kind of divorce that Sa Ra faced with Yul Seong. She asks Sa Ra to keep a secret that Yul Seong must not find out. Sa Ra seeks for a way to save Ji In in Solution's style. Sa Ra and Gi Jun feel mixed emotions while working together. They were apart for a long time, leading different lives, but both Sa Ra and Gi Jun still have the same traits that they used to find admirable in each other.

Yul Seong finally gets something on Ji In, and he begins a political show, using her. But Sa Ra can't bear to let this happen. She thinks giving up will only be her loss. She trains her mind and body with that spirit. An eye for an eye, and a tooth for a tooth! She begins fighting him back with an even better political show. Sa Ra has messed up with Yul Seong big time. The evil ex, Yul Seong. It's best to avoid seeing him alone.

An influencer with a fancy career, Choi La Hee, visits SOLUTION to seek a divorce consultation. Gi Jun is surprised to see her. La Hee doesn't seem that desperate for a divorce, and all of her attention is on Gi Jun. Sa Ra takes notice of that and works her hunches. Their solution goes to her husband instead of Choi La Hee herself. It's SOLUTION's first time to give a divorce solution to the client's spouse. They provide the fanciest and most dramatic solution to La Hee.

Yul Seong pushes things forward at full gallop to build a law school. To stop him, Sa Ra meets Kim Young A, the Hanjoo Party representative. But Young A consults her about an unexpected case. The SOLUTION team fights against the cosmic energy to stop Kim Young A's divorce. Gi Jun continues unraveling the story behind the Na Yu Mi case. He finally gets his hand on Professor Seo's phone and secures a critical piece of evidence. It turns out that the more they dig into this case, the more dangerous it gets for him and Sa Ra.

SOLUTION's extraordinary plan to destroy Pastor Cheonji continues. Will Sa Ra be able to get Kim Young A and the children out of Cheonji Dongsan? Sa Ra also comes up with a plan to strike Yul Seong on the Taking Kim Young A Down project. Who will be the winner of this intense war, Sa Ra or Yul Seong? Yul Seong decides to approach Sa Ra in a new way and offers a shocking suggestion to her.

Sa Ra can tell her change of heart. While her feelings toward Gi Jun are growing stronger, she has to prepare for the death anniversary of her mother with him. Gi Jun finds out that Sa Ra's mother was the informant who had gone missing. Sa Ra finds out that her mother was the Na Yu Mi case's witness and that Na Yu Mi might've not killed herself. She must reveal the truth behind this case, and the keyman is the part-timer Bae So Hee who worked with her mom.

Sa Ra goes back into Yul Seong's house despite everyone's opposition. She had already made up her mind, so no one could change her decision. They have no choice but to trust her decision. That's how the grand fraud show for Chayul begins. Once Sa Ra is in Chayul, she starts looking for the traces of the two cases. What kind of clue will she be able to find? A man who wears limited-edition sneakers was involved in both cases. The more they dig into him, the more confusing it becomes.

The truth behind Sa Ra’s mother’s death is revealed. Sa Ra comes up with a plan to make Yul Seong and Chairwoman Cha mistrust each other. Yul Seong gets arrested in the end, but he claims that Chairwoman Cha plotted everything. Meanwhile, Hui Jin reveals what Yul Seong did to Na Yu Mi in front of the investors for Chayul Town.

Ji In helps Sa Ra by handing over materials on the five-member society. Sa Ra also finds the ledger that Yul Seong kept hidden. Yul Seong kidnaps Sa Ra and threatens her to say that she faked the ledger. However, Gi Jun comes to her rescue, making Yul Seong pay for everything he’s done.