Spy no Tsuma

Set in 1940, Yusaku runs a trading company in Kobe, Japan and he is married to Satoko. While on a business trip in Manchuria, Yusaku learns of a horrific national secret. For the sake of justice, he decides to let the whole world know about his discovery. Satoko believes Yusaku, who is now accused of being a traitor. She swears to be with Yusaku no matter the consequences.

(Source: AsianWiki, edited)