The story unfolds in colonial Africa during World War One, close to Lake Tanganyika, an area where the boundaries between Rhodesia (British), the Belgian Congo, and Tanganyika (German) were established. It starts with a German assault on a village inhabited by Protestant missionaries in Rhodesia. Following this attack, a British boatman, who owns a steam barge called “African Queen” used for river transport, arrives. He picks up the deceased missionary’s sister, and they resolve to head toward the lake to strike against a German military vessel that is preventing British ships from passing. Now largely overlooked, it's one of those low-budget adventure movies about people performing improbable acts of heroism that most sensible individuals would avoid if given the chance. This flaw in the screenplay is the film’s biggest issue and its primary misstep: there’s no reasonable explanation for their actions or motivation to attack the Germans beyond a senseless sense of national pride. Despite this, it's packed with exciting adventures, humorous instances, and moments of peril that should keep audiences engaged. The movie includes two major stars in a less prominent role within their careers; Humphrey Bogart delivers an excellent and believable performance, aside from the obvious fact that he’s North American portraying someone in Africa, which was entirely under European control. A British actor would have been more suitable for the part. Katherine Hepburn also provides a strong and memorable portrayal. I did wonder if she was the ideal casting choice, as there seems no place for Americans within this narrative. Nevertheless, she clearly worked hard and gave a commendable performance. From a technical standpoint, the film possesses numerous strengths: filming in Africa presented the production team with immense challenges of every sort to bring the project to fruition, including tropical illnesses and logistical problems that are difficult to comprehend. The photography is remarkable, and the movie is visually appealing. The sets and costumes appear authentic, and the musical score complements the action well.

Source on TMDB