For genius actuary Ki-jun, divorce was the worst disaster of his life. Determined to turn it into an insurance product, he forms a team with his recently divorced neighbor, Han-deul, as an underwriter, and his ex-ex-ex-wife, Na-rae, as a quant. Thus, the divorce insurance project officially begins.

The team is astonished to learn that Na-rae, who joins the task force as a special advisor quant and a senior managing director at Plus General Insurance, is also Ki-jun’s ex-ex-ex-wife, though the two seem surprisingly unfazed. As the team pairs up to gather data for the divorce insurance policy, Ki-jun takes Han-deul to an unexpected place seemingly unrelated to their research.

The team works tirelessly, fully dedicated to developing a divorce insurance policy. After much effort, the team finally secures conditional approval. But to everyone’s dismay, Ki-jun leads them to a wedding fair to meet their subscriber target. However, Han-deul suddenly cancels all sign-ups at the fair, abruptly halting the plan for reasons unknown.

When Han-deul bumps into Ki-jun, weary from a run-in with his former brother-in-law, they begin to understand each other's demons of the past. Meanwhile, Na-rae and Jeon-man click and spark a mutual attraction, and Ah-young meets dancer and farmer Woong-sik on a blind date. However, as the task force gains momentum, they face a new challenge— rising divorce rates among their clientele.

Ki-jun and Han-deul rush to resolve a complaint that their divorce insurance subscription event violates industry regulations. Meanwhile, a policyholder couple's decision to get a divorce breaches both industry regulations and company conditions. The task force scrambles to locate the couple, only to discover that the husband, who holds the key to saving the divorce insurance, is missing.

Ki-jun and Han-deul get lost searching for Hyeon-jae when a looming shadow sparks fear—could the rumored tiger be real? They find Hyeon-jae just in time and escape. Upon reuniting with the team, they notice Mi-rae has come for Hyeon-jae but keeps her distance. With village head Woong-sik’s help, they find lodging and work to mend the couple’s rift while reflecting on their past and future.

"Would you like to live at my place?" In an effort to make Han-deul feel more comfortable, Ki-jun suggests they swap homes. Thanks to his thoughtful gesture, she gradually regains her self-esteem. However, when an elderly couple files for divorce, the divorce insurance faces a new challenge, sparking a heated debate within the team over the implications of late-life divorce.

Ki-jun and Han-deul have no choice but to explain their situation when Na-rae and Jeon-man catch them living in each other's homes. Meanwhile, evidence of Young-kyu's affair comes to light, voiding his divorce insurance subscription. This development helps the project avoid another crisis. However, for some reason, Han-deul suddenly tries to dissuade Seon-hee from proceeding with her divorce.

A leak of confidential company information about the divorce insurance leads to the shocking announcement of the team’s disbandment. The internal audit team suspects Han-deul, prompting Ki-jun and the team to work tirelessly to clear her name. Meanwhile, Jeon-man spots Na-rae in a private conversation with the vice president, leaving him conflicted. Will Han-deul succeed in proving her innocence?

Financial Supervisory Service Manager Kim visits the task force to announce his decision to get a divorce. When Han-deul insists the couple should split, Ki-jun struggles to hide his disappointment as her stance feels like a resignation from the project. Just then, Kim’s wife, Yeo-reum, declares she will never agree to the divorce, leading to a dramatic turn of events.

Ki-jun and Han-deul finally confirm their feelings for each other, deepening their love as she teaches him to weave with her favorite red yarn. Meanwhile, Ah-young slowly opens up to Woong-sik, and Jeon-man finds happiness with Na-rae, who decides to leave. As everyone navigates their newfound relationships, Dae-bok’s wife marks their wedding anniversary by filing for divorce.

The long-awaited launch of the divorce insurance leaves the team with mixed emotions. During their farewell getaway, everyone opens up and bares their deepest feelings. Later, Jeon-man decides to follow Na-rae to Singapore. Thanks to the insurance, Dae-bok reconciles with his wife and goes on an Aurora trip. Meanwhile, Ki-jun and Han-deul redefine their relationship, envisioning a happy future.