Every thousand years or so 2 witches and 2 wizards were born with a very special gift, the ability to change their physical form to a Dragon. Though there was a catch.
These 'Dragons' needed to find two things before they reached twenty. (The become A Dragon on their 19th) One, would of course, be another 'Dragon' which wasnt hard since there would only be 4 every thousand years and they did have a distinct marking of which they could tell thenselves appart from regular dragons. This Dragon (if it was the correct one) will become their mate for life.
The second, however, is alot harder to find, they would need to find their rider. This would be alot harder. Dragon riders are rare and almost extinct, is anyone sutible for these 4 new Dragons and whom exactly are the Dragons?