Mia Chenley goes on a forest villa vacation with her best friend Isla Hartwell and boyfriend Caleb Mercer. On the way, she dreams of being betrayed by them and everyone being swallowed by a giant python. Thinking it's just a nightmare, she tries to warn the others, but only she prepares in the basement. When the python attacks, those who believe her survive in the basement, while the ungrateful boyfriend and best friend face the consequences of their disbelief.