A delivery truck, transporting containers labeled "Specimens", with biohazard signs on them, crashes near a swamp after one of the containers breaks in transit. The creature, unseen, kills the drivers an escapes into the water. Then, we go to a young man, Chris, who is going on a boat trip with his friends. His mother turns out to be the local sheriff.
There's also a local black guy (Antonio Vargas) who has visions of the incident, and adds a needles supernatural aspect to this monster flick. Lots of people are killed. It turns out there was an infestation in Maryland, they were all caught but the chemical used to sterilize them just made them stronger. The sheriff and her ex-husband, who is a teacher at a community college, go to try to rescue their son, whose boat is stalled in the middle of the swamp. Yes--basically, this is a rip-off of the PIRANHA remake.