'Horizontal Collaboration' is a term used to describe the sexual and romantic relationships that some French women had with members of the occupying German forces during World War II. In this poignant, female-centred graphic novel created by writer/artist duo Carole Maurel and Mademoiselle Navie, the taboo of 'sleeping with the enemy' is explored through the story of a passionate, and forbidden, affair. In June 1942, married Rose (whose husband is a prisoner of war) intervenes in the detainment of her Jewish friend and then accidentally embarks on a secret relationship with the investigating German officer, Mark. There is only one step between heroism and treason, and it's often a dangerous one.