The story of a woman who struggles amidst a big whirlwind of fate, and her unconditional motherly love.

A patriotic bodyguard who was abandoned by his country and colleagues, a hidden daughter of leading Presidential candidate who regards love as a tool for revenge, and the First Lady contender who hides her ambition and charisma behind a kind and friendly personality.

Secret Investigation Record is based on cases detailed in the Annals of Joseon History with a bizarre twist; these incidents incorporate mysterious, supernatural elements that cannot be explained through science. Kim Hyung Do is an inspector of the state whose single-minded focus on his investigations into administrative misdeeds bring him into direct contact with these strange mysteries. Heo Yoon Yi is a government employee who aids him and attempts to understand these scientific impossibilities with an open mind, in contrast to his cynicism.