Sorata is an art instructor at Yamanoue School. At the young age of 20 he is already a full-fledged teacher with a meek and nerd-like disposition. Yet Sorata has a secret: he's Mouse, the internationally infamous thief.

多年前，楊碧芯因精神分裂險些毒殺兒子葉勁峰與女兒葉朗晴。勁峰遭逢巨變解離出體弱但高智的人格朱璣，朱璣苦讀成筆跡專家，助身手不凡的勁峰執行臥底任務。雙重炸彈案、血字裸屍案促總督察江政勳集合勁峰、精神科醫生韋睿傑、拆彈警花游雁星、法醫人類學家方菀芊組成特案組緝兇，竟譜出四人五角戀！刑偵之父聶山從躁鬱症康復，奉召帶領特案組調查種種懸疑奇案，卻發現碧芯似牽涉其妻梁日思失蹤之謎……當謎圖逐塊解開，各人如何面對？