"Roid Rage" is about Billy Beck, a steroid dealer who gets a designer drug from The UK that is equipped with dangerous livestock products that morph bodybuilders into superhuman killer machines.
Jack's Jacked Gym, the place that Beck sells his gear out of, is sponsoring a local amateur bodybuilding contest called "The Mega Muscles Contest" on Depot Island.
Spectators take a ferry out to the island and enjoy shopping at the array of local vendors and sponsors.
It is supposed to be a fun family day. But things are far from fun when Beck decides to inject the contestants with the experimental drug that he gets from England before the contest.
The handful of pumped-up hopefuls take the stage and strut their boldest and brightest poses.
Everything seems normal but then something happens...
The mad cow disease, mixed with the anabolic steroids, causes the ultimate roid rage and the hulking and angry contestants rush the crowd and begin snapping innocent spectators' spines like twigs.
The DEA is on the island to make a big bust but they are forced to team with Beck and several rogue survivors to battle a small crowd of mutated muscle monsters.