A teacher takes his class to a boat-trip on the Brussels-Charleroi channel, in Belgium. The majority of the students is made of adult african migrants attending a french language course. The class had to read the novel Heart of Darkness by Joseph Conrad as a homework. The teacher tries to gather impressions and comments about the book from his students, even by using explicit provocations. He chooses to concentrate particularly on the subject of colonialism and its implications on the relationship between the African and European populations. He obtains totally unexpected reactions that will lead to moments of conflict and tension.