A teenage rock musician masturbates gleefully and often. Way too often. One night, flying sperm escape and impregnate local women. The babies grow into an army of little creatures with the teen's head — and libido.

In the wake of a deadly SARS outbreak that's turned ordinary folks into flesh-eating zombies, Thailand stands alone as the only nation to block the pandemic. That is, until the virus finds its way into a crowded Bangkok apartment complex.