Four small-town friends battle an army of hump-happy zombies after a bizarre new product sends the locals into sexual overdrive. Dr. Jacob Pendelton is king of the infomercials, and his latest product ShamPube has taken the town of Slutton by storm. But little does Dr. Pendleton realize he's got enemies in high places, and they've tainted the latest shipment in hopes of destroying his reputation. Now anyone who tries ShamPube is overtaken by an uncontrollable urge to mount everything and anything in sight. Meanwhile, clueless pals Brian, Rick, Marvin, and Derik venture out to shoot a comedy skit that they hope will take the top prize in an upcoming film festival. As the streets fill up with gyrating zombies, Dr. Pendleton recruits the four friends to help stop the outbreak from spreading. But it's not going to be easy, because once you're humped, all hope is lost.