Rayearth is one of those interesting series broken up into parts. While this is volume four if this series, it's labeled as "Part Two: Book One." In the 25th Anniversary Edition, Part Two is in a different boxed set than Part One.

Hikaru, Umi, and Fuu are still reeling from their major battle that closed out Part One. The three try to adjust back to normal life, but the weight of what happened in Cefiro weighs heavy on them. The three meet up in Tokyo Tower again to try to come to terms with what has happened when suddenly, they are transported again! This time, the world they enter is in shambles. The ocean is gone, the sky is black, and the only thing they can see is a castle standing tall above a jagged, rocky island. The three are taken to the castle, where they reunite with what’s left of the old cast, and they are told what grim fate has befallen Cefiro. They also discover that there are several invading forces from other worlds desperately clawing at Cefiro’s borders, all vying for the chance to install themselves as a new ruler. Our Magic Knights pick up the mantle once again in defense of this once-beautiful world.

The final volume in part 1 of this series, and it's quite a whirlwind! This entire story seems like it happens over the course of one day, and moves extremely quickly.  In this volume, our heroines find all three Rune Gods and have to prove themselves worthy of their power.  Each one has a showdown with another Zagato minion, and has to outsmart them as well as out-fight them.  Through it all, the adorable Mokona guides them to every temple and conveniently hides during every battle.  Then, it's time for the final showdown with Zagato, and a twist ending you most likely will not see coming! 

In the Forest of Silence, where magic doesn't work, the girls meet a mysterious swordsman named Ferio, who seems to also want to become a Magic Knight.  Fuu strikes a bargain with him that forces him to escort the ladies to the Spring of Eterna in order to obtain the legendary mineral, Escudo.  The Spring is nothing like they all imagined, and the trial to obtain Escudo is more challenging than they were expecting.  Ferio lets it slip that only those close to the princess know of the legend of the Magic Knights, but he fails to say how he came across this information before he disappears into the wild blue yonder.  

As with many series of my childhood, Rayearth has been republished in a hardback anniversary edition with enlarged pages and beautiful covers. In honor of the 25th Anniversary, I will be providing reviews of every volume.  I have also reviewed this 6-volume series previously in one review. 

Rayearth begins with a mysterious young girl praying for the Magic Knights to save her world.  We then join several schools on a field trip to Tokyo Tower.  Three girls - Hikaru, Fuu, and Umi - from separate schools are singled out and pulled into a magical realm known as Cefiro (previously published as Cephiro).  These three ladies careen through the sky of a land that is very clearly not Japan.  They are rescued by a sorcerer, Guru Clef, who explains to them that the Pillar of Cefiro, the kidnapped Princess Emeraude, has summoned them to the world to become the legendary Magic Knights and save them all.  Clef bestows upon them magical armor and points them in the direction of a weapon-maker, just before he is overtaken by evil minions.  The three find out from Presea, the weapon maker, that they will need to adventure to obtain materials for their individual weapons, and all of this will culminate in awakening the Rune Gods in order to save Emeraude and Cefiro.