Rushing from the chaos of her student job, up the never ending staircase of her apartment building, Danielle, a West African-French student, calculates that she has enough time to change from her work clothes before her final sociology exam in 20 minutes. Her under maintained shoebox apartment has other plans. Yanis, a young concierge, comes to help and tries to fix the ancient door lock that has trapped her. As time trickles past the two strangers find an unexpected solidarity, with only a door to separate them.