Brynne Larson and Tess and Savannah Scherkenback are all-American girls from Arizona, who enjoy martial arts and horse riding. But something sets them apart from most teenagers - they perform public exorcisms and often appear on TV chat shows.
They are now karate black belts, but because of their particular Christian beliefs, they have also decided to do battle - they say - against evil spirits or demons. They believe that these demons can possess a human being and cause suffering, depression or addiction.
The young women have been trained by Brynne's father, the Reverend Bob Larson, who says he has performed more than 15,000 exorcisms.
They believe that the UK in particular is a hotbed for "witchcraft", because of the popularity of J K Rowling's Harry Potter books.
"The spells and things that you're reading in the Harry Potter books, those aren't just something that are made up, those are actual spells. Those are things that came from witchcraft books," says Tess.