Blurb of the first book in the trilogy: 

Earth has a twin planet, Lanu, where magic has evolved to an advanced stage, instead of technology. Six young people are mysteriously transported from Earth to this medieval alternative world (a dark, oppressive Narnia), where they are captured and enslaved by an evil king who dreams of combining the powers of magic and technology to conquer and rule over both worlds. Against his wicked sorcery, however, ancient forces of good magic, incarnated in the Last Golden Eagle, stir to life. First book of a trilogy.