丞相府嫡女沈砚奉旨女扮(bàn )男装,任(rèn )宫中侍卫。因未给皇后宫女(nǚ )让道,遭(zāo )其诬陷秽乱宫闱,旁支沈贵(guì )人与对(duì )手李万联手作伪证。沈砚从(cóng )容拆穿(chuān )谎言,当众摘冠亮明(míng )女子身(shēn )份,坦言(yán )乃陛下亲允的后宫(gōng )影卫。真(zhēn )相大白后,她揪出幕后主使(shǐ )三皇子(zǐ ),凭武力平定叛乱、护国安(ān )危,最终(zhōng )官至禁军统领,辅佐新帝,以(yǐ )女儿身(shēn )执剑守山河,成就双强共治(zhì )的传奇(qí )。