Doona! follows the story of Lee Doo-na, a former K-pop idol who abruptly retires at the height of her fame to live in a shared house near a university. Struggling with the pressures of her past life and a sense of isolation, she crosses paths with Lee Won-jun, a kind-hearted and ordinary college student who moves into the same house. As they navigate their daily lives, an unlikely bond forms between them. The series explores the complexities of fame, the burden of public perception, and the challenges of transitioning into a normal life. As Won-jun becomes a source of comfort for Doo-na, their relationship deepens, forcing them to confront their personal insecurities and the harsh realities of the entertainment industry that still threaten to pull Doo-na back into the spotlight.