Homer and Joé, two taciturn men aged around fifty, sail a small boat up a river in Croatia. Until recently, neither knew of the other’s existence, but now their father has died it turns out they are half-brothers. Looking for traces of the man of who shaped their lives so differently, they encounter a third traveller, the mysterious Irishman Sean, and their tour through the wild landscape of Croatia becomes a real psychological challenge.

»Certain people find it difficult to talk about themselves for many different reasons. My characters, Homer and Joé, halfbrothers, are such people. Homer, traumatised by an absent father who ignored his existence, Joé by the violence of this same father. The lack of words, of verbal communication interests me and can be found in a number of my films. The silences, what is left unsaid, leaves room for the spectator’s interpretation, their personal imagination. I like that. As to the narration, I have the impression that I am digging into earth that I already know but that I want to go deeper. If Joé and Homer are half-brothers, it is not by chance. In some of my previous films, blood-ties, filiation, the image of the father or his absence are strongly present. Upstream is part of this same lineage.«
– Marion Hänsel