In the bustling city of Seoul, amidst the shadows of towering skyscrapers and hidden alleyways, Heeseung and Serena find themselves entangled in a web of danger and intrigue. As operatives in a covert organization, they navigate a world where trust is a luxury and danger lurks around every corner. Yet, amidst the chaos of their missions and the weight of their pasts, they discover a refuge in each other-a bond that transcends the perilous world they inhabit. "Fatal Trouble" chronicles their journey of love and resilience as they confront their demons, unravel secrets, and forge a path towards a future defined by courage and hope.