Murray, James S. Don't Move (1982678321)

From the authors of the bestselling Awakened trilogy

Megan Forrester has barely survived the unthinkable. Six months ago, she witnessed a horrific accident that killed her husband and son, and lives with the guilt of knowing she could have done more to save them. Now, Megan hopes to mend the pieces of her broken spirit by attending a local church group's annual camping trip. But the church group members--riddled with dark secrets of their own--make a catastrophic navigational mistake, leaving them stranded in an untouched canyon in the West Virginian national forest.

Isolated from any chance of help or rescue, Megan and the others quickly realize why this side of the canyon has never been surveyed by humankind: it's home to a terrifying prehistoric arachnid that patiently stalks its prey through even the slightest movement or vibration in the forest. And it's desperate for a meal.

Grief-stricken and haunted by her tragic loss, Megan now faces her ultimate test of endurance. Can she outwit a bloodthirsty creature hellbent on ensuring that no one gets out alive? When a single wrong turn can mean death, she only has one option: DON'T MOVE.