Built up on a structure of an international noir thriller, Echo starts as from a devastating terrorist assault on the Paris subway. The event shakes all of France as a nation and is a start to an obsessive personal hunt across the oceans that leads spectators to the mountains on the Canadian-USA borders. On one hand, on the run, is the mysterious mercenary Orpheus. On the other, hard on his trail, is the charismatic chief-investigator of the anti-terrorism division in France. The police officer is tireless and feels he is close to his objective when he meets an extremely beautiful French widow, keeper of an obscure secret from World War II.