Joseph has an intensely close and ambiguous relationship with his sister Marianne. At her going-away party the day before she leaves to go abroad, Joseph is caught between his feelings for his sister and the advances by other suitors.

What happened, that 24th of December? This is what officer Chartier wants to find out. To understand, he will have to go back 48 hours earlier to Franck's Christmas eve. Franck is an insignificant drama-teacher by day, but also belongs to a nameless and leaderless militant organisation - the Animal Liberation Front. These characters are bound by a limitless empathy towards mistreated animals, and will have to show courage to complete a mission they have been preparing for months.