Little Nicky is "daddy's little girl" in Hell. He's the son of Satan, who got the job from HIS father, Lucifer. Satan wants to retire, but none of his sons are good enough for the job. There's Cassius, who's big and strong, but lacks the 'goodness' to make the job real. There's Adrian, who while really hot (no pun intended) and smart, has no goodness at all. Then there's Nicky [Sandler] who, while having good, lacks any evil whatsoever. As seen in the previews, he is told to release his evil. He needs to release it to save his dad. Cassius and Adrain leave Hell, thereby freezing the wall of fire that lets the damned souls into Hell. Since no souls can come in now, Satan starts to die. It's up to Little Nicky to go and get his brothers, putting them into a flask and bringing them back to Hell at the exact same time to save Satan from decomposition. If Nicky 'dies' on Earth, he will be able to get through the frozen wall and back up to Earth. The catch is that he has only a week, and that Adrian and Cassius are MUCH more powerful than he is.