Two young sisters, Lisa and Kate, are vacationing at a seaside resort in Mexico. The situation would be perfect for fun, but Lisa is upset that her boyfriend dumped her. So, Kate, the more laid-back of the two, tries to entertain her by taking her out at night to have some fun. Two young Mexicans invite the girls to experience the thrill of cage diving in a shark-infested place: totally safe, totally addictive. Lisa, worried, hesitates, but since her boyfriend left her precisely because she was considered boring, she decides, pushed by her sister, to try herself in life. Seeing the old rusty cage of “Captain” Taylor, Lisa is again overcome by doubts, but Kate is adamant: the adventure must be experienced. In the open sea, bait is thrown to attract the immediately arriving sharks. The girls then descend into the sea inside the cage to be able to enjoy the view of the sharks under their protection. But due to a technical problem, the cage falls to a depth of 47 meters, and the girls have problems with too little air and too many sharks.