Sharknado 4 takes place five years after the filmâs third installment (Sharknado 3: Oh Hell No!) which debuted last summer. In the movie, the world has been sharknado-free since the incidents of the last film when suddenly, the sharks begin to fly again powered by tornadoes. However, this time they are showing up in unexpected places and in unusual ways. Once again, it is up to Fin Shepard (Ian Ziering) to save the world.