Storyline:

Due to the sudden worsening of the weather, visibility on an airport bridge becomes extremely poor. Soon, a series of cars crash into each other and explode. The bridge itself is in danger of collapsing. People on the bridge are stranded with nowhere to go. Meanwhile, canines called Echo from the military's Project Silence, that were secretly being transported, are among those on the bridge. The dogs then escape from their cages. The survivors on the bridge become targets of these deadly animals. Various people on the bridge struggling to survive include Cha Jung-Won (Lee Sun-Kyun), Joe Park (Ju Ji-Hoon), and Doctor Yang (Kim Hee-Won).