Marcus picks up Regan's transmission and plays the high-pitched frequency through his portable radio before shooting the creature.
Once the kids find their way back to their mom, they realize that the feedback from Regan's implants distresses the monsters and weakens them for just enough time for Evelyn to shoot them.
.
Regan and Emmett cross the sea to an island, where they find a community of people enjoying life, seemingly untouched by the creatures.
The family moves on quietly, armed with their guns.
Forced to venture into the unknown, they realize the creatures that hunt by sound are not the only threats lurking beyond the sand path.