D'Artagnan, on a quest to rescue the abducted Constance, runs into the mysterious Milady de Winter again. The tension between the Catholics and the Protestants finally escalates, as the king declares war — forcing the now four musketeers into battle. But as the war goes on, they are tested physically, mentally and emotionally.

家庭优渥、生活幸福的县令之女薛芳菲在遭逢巨变之后失去一切，受救命恩人、中书令之女姜梨之托，以姜梨的身份回到京城，并在肃国公萧蘅等人的帮助下，克服重重艰险，不断努力对抗不公，最终救出意外入狱的父亲，并帮助萧蘅匡扶正义，守护黎民百姓。
剧集改编自千山茶客的小说《嫡嫁千金》。

D'Artagnan, a spirited young Gascon, is left for dead after trying to save a noblewoman from being kidnapped. Once in Paris, he tries by all means to find his attackers, unaware that his quest will lead him to the very heart of a war where the future of France is at stake. Aided by King's Musketeers Athos, Porthos and Aramis, he faces the machinations of villainous Cardinal Richelieu and Milady de Winter, while falling in love with Constance, the Queen's confidante.

Hari finds himself trapped in a mysterious prison. An assassination attempt leaves Day shaken. Gaal and Salvor devise an escape plan.