The storm

For the majority of the novel, a storm rages, cutting the island off from the outside world. The storm operates as both a plot device and a symbol. It prevents anyone from leaving the island, forcing them to stay in the shelter of the house where the murderer has total control. In this sense, it allows the murders to occur. It also cuts off the victims from civilization. There is no electricity, no cell phone reception, and, eventually, no internet service. Those factors increase the characters' dangerous predicament and sense of isolation, allowing the killer complete control over them. Like it or not, they are stuck on the island with someone who wants them all dead.

The storm also symbolizes Tom's fury at the injustice of his sister's death. He feels that her peers bullied her. His behavior throughout the novel is like the storm...