A young stowaway, Aziz, jumps into the icy waters of Boston Harbor and swims ashore. He scrabbles to find shelter with fellow immigrants, tries to live right, but quickly learns that the normal rules don't apply to those who have no legal existence. Just as Aziz allows himself to forget the atrocities he fled back home in Algeria and to imagine a brighter future, the FBI starts taking an interest in his circle's activities, and all assumptions - his and ours - dissolve into urgent questions: how are terrorists identified? who watches them? and how do they live in our midst and how do they evade us?