Being a Choshu clan member, Kusaka Touma wants Japan to develop good relations with foreign nations. To achieve this, he attempts to learn English behind his clan's back. Therefore Akizuki Keiichirou 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.

He has a mild and gentle character which even doesn't let him draw his sword although his life is in danger.