Mahiro Aizawa and Naoto Igarashi are a married couple whose relationship has soured, leading them to live separately. After Mahiro quits the company where they both used to work, she finds a new job at an interior design or furniture consultancy firm where she quickly proves herself as a capable and popular employee. However, her fresh start is upended when Naoto, unaware of her new place of work, also joins the same company and even becomes her superior. To avoid awkwardness and office gossip, the estranged couple agrees to keep their marriage a secret and pretend to be complete strangers to their new colleagues.

The story follows Mahiro and Naoto as they navigate this precarious double life. The lie forces them to interact professionally while privately confronting the unresolved feelings and issues that drove them apart. Flashbacks reveal the root of their problems, stemming from their clashing personalities: Naoto is a neat and orderly person who grew frustrated with Mahiro's more relaxed and untidy habits, while Mahiro felt hurt by Naoto's constant criticism and her own inability to voice her needs, eventually causing her to leave and block him.

Their secret is threatened by the interference of new coworkers. Hayashi, a female colleague, becomes interested in Naoto after believing he is single and begins scheming to get closer to him, at one point even spending the night at his apartment under false pretenses. Meanwhile, Seto, a quiet male coworker, develops feelings for the kind and attentive Mahiro. Hayashi's jealousy eventually turns malicious when she orchestrates a compromising photo of Mahiro to spread through the office, creating a major rift between the secret couple.

As the series progresses, Mahiro and Naoto are forced to confront their true feelings. Through these trials, including a company trip where they finally reveal their secret to Hayashi and Seto, they begin to understand each other's perspectives better. After Naoto receives a job offer to work in Singapore, they must make a difficult decision about their future. Ultimately, they choose to get a divorce not as an end, but as a way to reset their relationship, agreeing to start over from zero with a clean slate, promising to be together again when Naoto returns from abroad.