The film follows Tania and her 13-year-old son Ivan, two illegal Russian aliens living in Belgium. After being denied Belgian permanent residence, Tania deliberately burns her fingers to remove her fingerprints and avoid identification. Tania advises her Belarusian friend Zina to apply for political asylum, since Belarus is considered a dictatorship by Belgians, but Zina seems to dismiss Tania's advice.

Tania is caught, but she tells Ivan to run. She refuses to tell her name, hoping to be released after 5 months, as she is told by another illegal. Ivan comes to live with Zina. Tania is eager to start working in the detention center to earn money to phone him from time to time. Ivan wants to start working to earn his living. However, Tania is worried that it will be criminal work. Ivan wants to visit her, but she does not want that, it could make things worse. Authorities threaten to put her in jail for two years for giving a false name when applying for medical insurance.

Desperate, Tania identifies as Zina and applies for political asylum, as a Belarusian. But then she is surprised to learn that Zina has already asked for asylum before, in Poland. Eventually Tania (as Zina) is forced into a plane to be deported to Poland. However, other passengers protest, and she is taken off the plane. After being beaten on her way back to the detention center, she awakens in a hospital, and manages to escape the sleeping guard, to finally reunite with her son Ivan.

• Anne Coesens as Tania
• Alexandre Golntcharov as Ivan
• Christelle Cornil as Lieve
• Frédéric Frenay as Policier 1
• Esse Lawson as Aissa
• Olivier Schneider as Policier 2
• Shirley Rumierk as Maribel Chacon

• List of submissions to the 83rd Academy Awards for Best Foreign Language Film
• List of Belgian submissions for the Academy Award for Best Foreign Language Film

• Illegal at IMDb  
• Illegal at AllMovie