The book Heart of Darkness and the movie Apocalypse Now have a similar plot but takes place in different times and a world apart. Apocalypse now is a modern version or interpretation of the book Heart of Darkness written in 1902.
The theme of in both is that of a white man traveling to a foreign country where they dominate their own crew as well as the natives. Both character in the book and the movie Marlow and Willard see the selves as the civilized and the natives as savages. The plot of both becomes a journey in to the jungle but also into themselves. One thing that is similar between the Marlow and Willard is their sympathy for Kurtz, and that they both see a little bit of themselves