A fun ride down the Ulanga with Bogey and Hepburn, in a comedy of manners, action, adventure and romance.
Bogart plays Charlie Allnut, an aging, grizzled drunkard who runs supplies to the villages up and down the Ulanga river in Africa. Katharine Hepburn plays Rose Sayer, the sister of a missionary working in a village on the Ulanga. It's World War I out in the world, although that means little to people in the wilds of Africa. Rose knows nothing of it, and Charlie only a little.
What they do know, and too late, is that the Germans have arrived in Kenya and are conscripting local villagers. They also have a battleship in the lake at the mouth of the Ulanga that's wreaking havoc.
When the Germans and their African conscripts destroy Hepburn's mission village and kill her brother, she and Bogart take off down the Ulanga to escape. Hepburn's determined to aid the war effort, but Bogart knows the river and its dangers.
This starts a continuing squabble, as does the presence of a refined lady in the old coot's boat. Try as he might to be respectful (it's strange to see Bogey so conciliatory), Rose demands more.
The story takes off with their trip downriver, full of adventure and romance. A must-see.