The Beach Killer is a horror film.
Five friends ;Katie, Kellie, Amy, Robin and Marcie, go to the beach on a hot summer's day. They pick out a spot in the sand dunes and start drinking and smoking.
Robin leaves to use the nearby toilet facility. While she is peeing, a guy named James arrives and pees in the stall next to her. They both notice a glory hole in the wall and Robin has James put his penis through it so she can have anonymous sex with him. Whe he prematurely ejaculates, she gets angry, so he shoves her and she hits her head on the sink, killing her.
Meanwhile, James' friend Reece encounters the other girls and starts flirting with Amy. Marcie goes to the toilet to look for Robin, becoming worried as she has not returned. She instead catches James trying to move the body, so he strangles her to death.
Reece and Amy sneak away and go into the bathroom to have sex. Afterward, Amy goes to pee and James convinces Reece to help him move the bodies. Amy overhears this, so Reece kills her.
Katie and Kellie are the last to go to the bathroom. Kellie convinces Katie to snort some cocaine and they start having sex. They catch Reece watching them, but rather then getting angry, they decide to have him join in and start having sex with them. Reece becomes too rough and chokes Kellie to death.
Katie flees but is chased to Reece. James intercepts them and hits Reece with a rock, killing him. Katie is thankful to James and has sex with him on the beach, before James convinces her to help him hide Reece's body. She then discovers the bodies of the others, but James hits her with the rock and buries them all together on the beach.