在幕末的动乱时期，在这个危机的时代，开国论者草加十马（三木真一郎 配音）和德川幕府的幕臣秋月景一郎（森川智之 配音）相遇了。二人一相遇便互生好感。草加更是对秋月的理念赞赏有加，而秋月则欣赏草加的开明和前瞻性。在草加去伦敦学习的前夕，互生情愫的二人终于向对方传达出自己的情意，约定回来后相见。但当二人再次相见时，却是在战场上。而此时的秋月却已断了双腿，被战败弄得意志消沉。草加将秋月安排到了自己家，悉心照顾。但身处对立面的二人终究抵不过这时代的悲剧。就像这“冬之蝉”，生在了错误的季节，终究逃不掉悲剧的命运。

本片改编自新田佑克老师漫画《拥抱春天的罗曼史》的前传《冬之蝉》。共有三部分别是《江户恋歌》、《虾夷战记》和《东京悲话》。

During the late Tokugawa period, tensions between the bakufu and Chōshū clan are rising due to arguments over how to deal with foreigners in Japan. However, unlike the rest of the Chōshū clan members, Touma Kusaka wants Japan to develop good relations with foreign nations. To achieve this, he attempts to learn English behind his clan's back. A man named Keiichirou Akizuki decides to become Kusaka's teacher, but their relationship soon grows into something stronger, despite the fact that Akizuki works for Kusaka's clan's enemy, the Tokugawa bakufu.