Dr. Emma Collins continues the work of her deceased father on the protection of great white sharks on an artificial island near South Africa named Little Happy. Her team includes Spinnaker (nicknamed "Spinn"), Miya, and Eugene Shaw, Emma's father's best friend and brother figure. Also living on Little Happy are Emma's friends Nandi and her brother Bahari. Bella, a bull shark who was responsible for the chaos in the past years, is found dead, having been killed after getting stuck in fishing lines, discovered by Dr. Richard Lowell and his team on their boat, the Thasos. They go to Little Happy to find the three last pups of Bella are now adults, and are the only survivors from the litter.
Richard is revealed to be Emma's ex-boyfriend. When Richard and his team dive to chase the bull sharks, Emma goes with them and discovers three great white sharks devoured by the bull sharks. Soon after, Brown (a member of Richard's team) is found dead, having been sliced in half by the bull sharks. With Emma's help, one of the biggest bull sharks is sedated and captured but Richard is injured.
Later, Bahari goes fishing but is attacked and devoured by one of the two remaining bulls. Nandi later discovers his severed arm. After the loss of her friend, Emma confronts Richard. He reveals to her that these bull sharks are more intelligent, telling the events of the first two movies. He says that with the beacon which was attached to their mother, he can attract her offspring as they know that their mother is dead. He concludes in saying that if these sharks reproduce, it will be a catastrophe. Lucas, leader of the mercenaries of Genotic Labs, overthrows Richard's command and decides to kill everyone and flee with the captured shark. They place a mine to blow everything up, unaware that Emma and her team is spying on them with an underwater drone.
Emma confronts Richard again, accusing him of planning to murder them. Lucas, having overheard their conversation, attacks them and Emma's team, causing massive damage to nearby structures on the island with explosives. During the battle, Emma escapes, but Richard is captured by Schill and Earls, Lucas's men, and brought to the Thasos.
After choosing Emma's side, Richard is killed by one of the sharks as he jumps from the boat to join her. Earls is killed by a bull shark while he fights with Shaw. Meanwhile, Spinn is killed by a bull shark and Miya is presumed to suffer the same fate. Emma deactivates the mine but is attacked by Schill, who has been instructed by Lucas to kill her. She is saved by Sally, the great white shark, "friend" of Emma since her arrival on Little Happy, who devours Schill. Emma places the mine on the Thasos and when Lucas explodes it, his boat sinks which frees the captured shark.
Shaw sacrifices himself to kill two of the three bull sharks with explosive darts. Lucas, having survived the recent explosion, attacks Emma, but is killed by her and Nandi. Emma then kills the last bull shark by luring it into the garbage compactor.
Nandi and Emma flee, leaving Little Happy destroyed, with Sally addressing a goodbye to Emma before disappearing into the ocean. While Nandi and Emma navigate, they find a wardrobe and Miya is revealed alive, having hidden inside it. Reunited, the three friends go back to civilization.
On Rotten Tomatoes the film has an approval rating of 73% based on reviews from 15 critics, with an average rating of 5.6/10.[7]
Meagan Navarro of Bloody Disgusting expressed that while the film cannot be considered good by conventional standards, it was nonetheless enjoyable.[8]
