We have studied how eliciting historical empathy in a class of 13th grade students through using the film "12 Years a Slave" (McQueen, 2013) supported their in-depth understanding of slavery in nineteenth-century USA. Historical empathy is one of the core elements of the new curricular reform implemented from 2020 in Norway, and it is believed to have potential to strengthen: (1) students' future citizenship and participation in democratic and multicultural societies; and (2) students' in-depth understanding of history. We implemented a five-week lesson plan with different activities based around the film, and used students' assignments to evaluate their feelings about the lessons and their historical understanding of slavery. The results confirmed the potential of film to enhance historical empathy when the screening is well prepared and combined with relevant activities. Students demonstrated a high level of engagement and managed to perform complex tasks. Both their ability to contextualise and to 'care' improved. Particularly, students' historical understanding of slavery was boosted by the group conversations and the dialogic nature of the activities in the classroom. In addition, we observed a greater positive influence on boys' achievements compared with girls' -- a finding which is interesting in a wider educational context and which needs further exploration.