A Hasidic Jewish woman in Brooklyn flees to Berlin from an arranged marriage and is taken in by a group of musicians — until her past comes calling.

Mercer's brother, an amateur pilot, crashes on an island and is killed by a giant spider. A year later, when Mercer goes in search of him, she discovers a breed of poisonous arachnids ready to attack.

After a personal tragedy, Sarah joins her friends on a caving expedition in the Appalachian Mountains. But when a rockfall traps them deep underground, their adventure turns into a nightmare. As they search for a way out, the group discovers they are not alone—lurking in the darkness are savage, cave-dwelling creatures. With rising tension and dwindling trust, the women must fight to survive against both the predators and each other.