太傅嫡(dí )女沈宛宛与宁(níng )国侯世(shì )子萧至大婚在(zài )即,萧至的青梅赵茵儿(ér )将正室嫁衣换(huàn )成妾室粉色嫁衣,当众(zhòng )羞辱沈家。萧至(zhì )偏袒赵茵儿,让沈宛宛(wǎn )忍让。沈宛宛不(bú )甘受辱(rǔ ),借皇上赐婚之(zhī )机,改嫁给萧至驻守边(biān )关的兄长萧宸(chén ),助萧宸取而代之成为(wéi )世子。赵茵儿自(zì )食恶果沦为姨娘,萧至(zhì )失势后自甘堕(duò )落,竟勾(gōu )结二皇子与北(běi )狄通敌,暗害萧(xiāo )宸。沈宛(wǎn )宛与萧宸将计(jì )就计,大破北狄,揪出萧(xiāo )至与二皇子罪(zuì )证。最终萧至被斩,奸人(rén )伏法,二人镇守(shǒu )边关,安稳度日。