When two bumbling employees at a medical supply warehouse accidentally release a deadly gas into the air, the vapors cause the dead to rise again as zombies.

A group of kids discover one of the drums containing a rotting corpse and release the 2-4-5 Trioxin gas into the air, causing the dead to once again rise from the grave and seek out brains.

Having recently witnessed the horrific results of a top secret project to bring the dead back to life, a distraught teenager performs the operation on his girlfriend after she's killed in a motorcycle accident.

In an attempt to rescue their friend from an evil corporation, a group of teenagers end up releasing a horde of bloodthirsty zombies.

A student creates and sells a drug called 'Z' which has the unexpected side effect of resurrecting the dead as flesh-eating zombies, who proceed to wreak havoc at a Halloween rave.