Wishmaster is the first film in a horror series that deals with people trying to outsmart an evil djinn. They must make their wishes, but if they make three wishes, then the djinn can tear open a rent between worlds and bring in the rest of its kind. So the one that holds the gem has to be careful what they wish for and somehow trick the djinn into sealing itself away.
Wishmaster begins in ancient Persia, showing the djinn trying to coerce a sultan into making his second and third wishes. Before he can make the third wish, the djinn is bound into a huge fire opal. The movie fast forwards to the modern day, where a drunk crane operator drops a box containing a statue. The box kills a man, and the statue shatters, revealing the fire opal that contains the djinn. A dockworker pawns the stone, and it comes to an auction house where it's given to the appraiser Alexandra Amberson (Tammy Lauren). She awakens the djinn, and as such as three wishes that she must make.
Through a series of events, the fire opal explodes in an examination lab, and the djinn kills Alexandra's crush, Josh Aickman (Tony Crane). Alexandra begins investigating the statue and the gem, and the djinn sets about granting wishes to people. With every wish it steals a soul, and with enough souls it can tear open the gap. But before it can do that, it has to grant Alexandra her three wishes. So the djinn tracks her down, and even gives her a sample wish for free. She wishes for it to kill itself, but since it's immortal, the gunshot wound to the head does nothing.
Alexandra uses wish one and two to understand the djinn and to get away from it. Finally, under the pressure of the djinn's threats, Alexandra lastly wishes that the dockworker hadn't been drinking. This undoes it all, putting everything right.