- "Half Zombie. Half Demon. All Zemon!"
Casper is a college student hanging out with his friends as he watches his grandfather's occult shop. During this meet up, they accidentally break an ancient jar. This jar had a dark spirit in it, who causes everybody the kids encounter to be Driven to Suicide. It then possesses the corpses to become zombie demons, or "zemons," as our heroes refer to them. The friends then have to contend with these zemons while trying to reverse the curse by daylight, or else it will be permanent.
This film contains examples of:
- Actor Allusion: When the occult bookshop owner, played by Christopher Lloyd, learns of the Ash Demon's return, he exclaims "Great Scott!"
- Big Bad: The Ash Demon controlling the zemons.
- Generic Doomsday Villain: The Ash Demon is an incorporeal force that is freed format prison and immediately starts zombifying the populace with no rhyme or reason behind it.
- Here We Go Again!: The Ash Demon is sealed away, and time is rewound so that nobody actually died. Last shot of the film involves Casper accidentally breaking the urn again.
- I Love the Dead: Seth decides that zemon!Lucy is gonna be his girlfriend after he manages to bind her to his will.
- Our Demons Are Different: These are dark spirits that can cause suicides and raise the dead.
- Our Zombies Are Different: These are raised by demons as Mooks.
- Precursor Hero: Casper's great-grandfather was a Hunter of Monsters who captured the Big Bad first time around.
- Psychic-Assisted Suicide: The Ash Demon acquires zemons by influencing people to commit suicide so it can possess their corpses.
- Reset Button: The spell to trap the Ash Demon turns out to be this, rewinding time to just before it was released.
- Suicide as Comedy: Half the jokes in this movie are related to the increasingly over-the-top ways the victims of the zemon curse kill themselves.
- Wrong Genre Savvy: Patrick thinks that he's The Bully in a college romcom, when he's really the Cannon Fodder Jerkass in a zombie film. This gets him eaten by zemons.
- You Killed My Father: Casper;s father was slain by the evil force in front of him when he was a child.