Also known as a magnetic fusion drive, or a mega-ion drive.
A staple of high end sci-fi is the replicator or the nano-assembler. There is a much more practical and less technomagical way to achieve the same goal. The exciting thing is that this technology exists now, and we're getting much better at it.
The party comes across a nice hermit in the woods. He gives them food and lodging for the night. They awaken to his terrified screams. "East! It's east! Stop it! It'll kill us all!" The poor horror-stricken hermit dies thrashing in agony, one boney arm outstretched, his finger pointing to the east.