Han So Yeon works as an assistant manager at a glasses company and performs well at her job, yet she lives an isolated life because she cannot recognize faces. Her condition makes social interaction difficult, and she keeps her distance from others to avoid confusion and embarrassment. Everything begins to change when she becomes a tester for Holo, a hologram AI designed to support its user with absolute loyalty.
Holo is programmed to understand and assist So Yeon, but through their time together, the AI starts to sense the limits of its own nature. The situation becomes more complicated when Go Nan Do, the real creator of Holo, enters her life. Nan Do has lived in hiding for years after faking his death in the aftermath of a major hacking case. He shares the same appearance as Holo but has a completely different personality.
As So Yeon interacts with both the AI and its withdrawn creator, their lives begin to overlap. Holo helps her open up to the world, while Nan Do confronts emotions he has never allowed himself to feel. Their story follows three lonely individuals connected by technology, identity, and the possibility of love.