After their city floods with water, the people of Santa Monica, California, find themselves up against enormous sharks when a violent hurricane hits the shore.
On their way to New York City to promote April's book "How to Survive a Sharknado and Other Unnatural Disasters", Fin and April find themselves trapped when a hurricane sweeps the city, bringing heavy rains and Sharknadoes, while they try to save the city.
When Washington is hit by a tornado that unleashes monstrous sharks, Fin steps up one more time in an attempt to combat the onslaught. But when the sharks converge to make a huge terrifying monster, he enlists the help of a few friends to find a solution before the East Coast gets decimated.
The five-year-peace is shattered when Fin learns that troubling clouds are on the way, and yet another shark-infested tornado is about to devastate Vegas, forcing him to team up with both old and new friends to face the upcoming mayhem.
When massive sharks begin attacking people, Fin and his wife April are compelled to go on a dangerous journey to retrieve their little boy, who is stuck in a distant location.
Following his survival from a massive shark attack, Fin travels back in time to save his family and the planet from a hurricane that resulted in a shark invasion.