Here's a little about Scientology:
It was founded by a science fiction writer named L. Ron Hubbard in 1952. It was originally supposed to be a self-help philosophy.
This self-help philosophy is called Dianetics, and is meant to free your "thetan," or soul, from the souls of aliens that are attached to it.
Xenu was an alien dictator of the "Galactic Confederacy" who, 75 million years ago, brought billions of aliens to Earth in DC-8-like spacecraft, stacked them around volcanoes and blew them up with hydrogen bombs. Their souls then clustered together and stuck to the bodies of the living, and continue to wreak chaos and havoc today.
Human thetans are millions of years old, having been reincarnated over and over, with these alien souls attached.
According to the Church, the ultimate goal is to get the soul (thetan) back to its native state of total freedom, thus gaining control over matter, energy, space, time, thoughts, form, and life. This freed state is called Operating Thetan, or OT for short.
I didn't make up any of that.