Ko Gyeol, a brilliant architect living a flawless life, returns to his hometown after ten years at his grandfather's summons and enters a fierce succession battle within Kangsu Group. As head of Strategic Planning at Kangsu Construction, he relies on cold logic and calculated decisions to seize control. Meanwhile, Cho Eun-ae, a startup developer dreaming of a humane AI-driven world, fights to reclaim her company, Lucky Joy, after it is seized by Kangsu Construction. Their clash over "Joy," the AI at the center of it all, sparks intense rivalry between Gyeol and Eun-ae, but an unexpected incident forces them into an unlikely partnership. Amid conflict and cooperation, they grow closer, navigating a journey to take ownership of their own lives.