Megan Bradley and the rest of the witches were rounded up by a religious crusade and forced onto a spaceship for a 190-year multi-generation trip to another star. They soon discovered the ship had problems and would run out of air long before they reached their destination. They were forced to use magic to get to their destination faster, before they suffocated.
But then, of course, they had a whole new world to cope with...
Nobody but Kendra could see into the large cauldron, but soon the watchers noticed its contents were casting a strange green light on the ceiling. When she finally decided things were ready, Kendra opened the valve on the large pipe, and called to the tech at the control panel, "Start the ship's engines." He threw the switch, and after a moment there was a low rumble, similar to that during the first year of the voyage. Nothing else seemed to be happening.
Then someone who was facing the viewplate cried "Look!"
On the viewplate the stars were moving. Soon they were racing across the plate, faster and faster, as the ship gained speed, and after a while it was impossible to distinguish points of light, just streaks. One of the techs stared at the viewplate and said, "I don't believe this is happening, it violates every law of physics! But seeing those stars, we must be moving at several hundred times the speed of light." People started cheering.