Two American girls travel to Montenegro on vacation to visit an old friend. While there they decide to venture to Mamula, an abandoned military fortress located on a remote island. During their exploration of the fortress they discover that they are not alone. Someone else is on the island with them and he will stop at nothing to protect it's secrets. There is a darkness hidden beneath the island and the terror has just begun. 　　译文(3): 两个美国女孩去黑山度假去看望一位老朋友。在那里，他们决定冒险前往马穆拉，这是一座位于偏远岛屿上的废弃军事要塞。在他们探索堡垒的过程中，他们发现自己并不孤单。其他人和他们在岛上，他会不择手段地保护岛上的秘密。岛下隐藏着一片黑暗，恐怖才刚刚开始。