English

City Hunter The Movie: Angel Dust

Japanese

劇場版シティーハンター 天使の涙 (エンジェルダスト)

It is based on the manga finale, where Ryo Saeba faces his dark past that his former mentor and adoptive father Shin Kaibara from now on leader of Union Teope would want to kill him, as the people who are injected with nanomachines to become super soldiers, aka Angel Dust, are starting to kill him.

(Source: City Hunter Wiki)