After the first wave hit, the lights went out. After the second wave, the lucky made it out alive. After the third wave, only the unfortunate survived. After the fourth wave, you couldn't trust anyone. After the fifth wave, Cassie finds herself fleeing the beings that look like us. She knows her only way to stay alive is to stay alone. When she meets Evan, he strikes her as someone who could help her find her little brother. The moment has come for her to make a decisiontrust him or give up hope and abandon the fight.