Matt Hotson & Amy Jo Johnson 
Mighty Morphin Power Rangers: The Return #3 [PDF ebook] 

A new adversary reveals the secrets of the final battle and deadly explosion on the moon all those years ago, but what implications arise when the long-thought dead are more restless than the Rangers thought? A secret hidden on the moon only survived after the sacrifice of another, and it will be up to the Rangers with some unexpected help to protect a vulnerable Earth. And when the plan is enacted, what role will the Dragon Power Coin play ?