Eighteen-year-old Aihui Ying dreams of becoming a brilliant engineer just like her beloved father – but her life is torn apart when she arrives a moment too late to stop his murder, and worse, lets the killer slip out of reach. Left with only a journal containing his greatest engineering secrets and a jade pendant snatched from the assassin, Ying vows to take revenge into her own hands. Disguised as her brother, Ying heads to the capital city, and discovers that the answer to finding who killed her father lies behind the walls of the prestigious Engineers Guild – the home of a past her father never wanted to talk about. With the help of an unlikely ally – Aogiya Ye-yang, a taciturn (but very handsome) young prince – Ying must navigate a world fraught with rules, challenges and politics. But to survive, she must fight to stay one step ahead of everyone.