一名勝訴率10%的生計型律師偶然被捲入一宗命案，一夕之間成了絕世天才詐騙犯「大老鼠」。為了保命及守護家人，他將揭發策劃巨大陰謀的腐敗權貴的真面目。

22年前雙胞胎兄弟宇信和秀玄因一起命案失去了父親。如今成為暢銷推理小說家的宇信發現被用來殺害他父親的兇器是一支名為阿達瑪斯的鑽石箭，為了得到它，他以自傳代筆作者的身分進入了海松集團權宰圭會長的宅邸。而成為中央地檢特搜部檢察官的秀玄則和試圖揭開22年前真相的記者瑞熙見了面，並對父親的死存疑，開始重新追查這起案件。雙胞胎兄弟倆將以各自的方式追查案件的秘密並揭開真相。

Dark Minds brings together the sharp criminal minds of author and investigative journalist M. William Phelps and pre-eminent criminal profiler John Kelly to reopen unsolved homicides thought to be the work of serial killers. They are assisted in their efforts by a source known only to viewers as "13," a convict serving multiple life terms for a series of murders, who presents his theories about potential motivations behind these chilling cold cases based on his own experiences. They bring fresh eyes to unsolved serial killer investigations using the combined instincts of three unique perspectives, with hopes that it will encourage viewers to bring forward new leads.