Night Raid 1931 - Season 1 Episode 5 A Negative Summer

Kazura recognizes his old friend Nishio in a photograph that Aoi has taken in a German delegate's house, resulting in Kazura investigating Nishio's whereabouts. However, he is captured and tortured by the Kuomintang and discovers that Nishio is a spy for the Communist Party of China. Released in exchange for information regarding a weapons smuggling involving the Comintern, Kazura approaches Nishio's lover Ailin, and the two briefly talk about him. During the weapons smuggling, Nishio escapes from the authorities and crosses paths with Kazura, who informs him that Ailin is waiting for him. Nishio disregards it and is later assassinated.