Lord Beldaruit tells Coco a story of Qifrey’s past and why he has such a strong prejudice against the Brimmed Caps. Because of this, Coco decides to break off from the group and go to the Tower of Tomes to seek answers for Qifrey’s struggles as well as seek a solution for her own mother. But getting to the Tower proves to be much more perilous than Coco believed it would be.  The Tower is guarded by fierce water dragons that spring out of the lake and attack any movement they sense on the banks of the lake.  Qifrey races after her to save her from the guardians of the Tower, but he's still not fully healed from his previous injuries, and he must rely on Coco's originality and ingenuity to save them both.

The Sailor Scouts have a new enemy who has put a spell over the entire Jûban district of Tokyo, and is setting loose little concentrated spheres of evil - lemures - to turn all the beautiful dreams into nightmares. This new enemy is headed by Queen Nehellenia, the queen of the New Moon, of the dark side of the moon. She has found a way in through all the protections on Earth, and is attacking it from the inside. The Dead Moon Circus is her front to besiege the people of Jûban, and her efforts are affecting Mamoru-san. To complicate things even more, the scouts find they can’t transform in the face of this new enemy, but instead have to gain a new power up.

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.

Coming off the interruption of the Second Test for Agott and Richeh, the apprentices and Master Olruggio travel to the Hall of Witche, where they can get medical attention for the badly injured Master Qifrey, and where they have to answer the questions of Lord Beldaruit, Wise of Teaching, about what happened during the test. The apprentices show Coco around the Hall, and she continues to be amazed by the magic employed by witches. The apprentices are also given a make-up test opportunity: they must surprise Lord Beldaruit, wise of teaching, who seems to be not easily impressed, with some form of magic that will rekindle his awe for magic. But, instead of the rest being just for Agott and Richeh, Beldaruit gives all of Quifrey’s apprentices the opportunity to take and pass the Second Test, including Coco.

This is a mega-sized volume with the conclusion of the Death Busters arc, and inclusion of two side stories.  Mistress 9 tries to use Chibi Usa's hostia and the stolen Mythical Silver Crystal to provide enough power to Master Pharaoh 90 to merge with Earth and make it their new home planet, However, Mistress 9 wasn't counting on her host's body being so difficult to control. And, after Mistress 9 awakened, no one thought the final Sailor Scout would awaken.  The conclusion is sweet and wrapped up pretty tidy, but the final pages, of course, hint that the peace they just achieved is threatened again.  There are also two side stories in this volume, contributing to its girth.  Chibi Usa's second Picture Diary, "Beware of Tanabata," is a side-adventure where an enemy uses popular Sailor Moon watches to manipulate the emotions of young girls. The second side story is "The Love of Princess Kaguya."  This beautiful story focuses almost entirely on Luna, and her falling in love with Kakeru, a human astro-physicist who saves her from being run over by a car.  Kakeru and his childhood friend, Himē, both pledged to become astronauts and travel to the moon to see if the Princess Kaguya from legend really lives there.  A new enemy manipulates Kakeru and puts his life in danger, while Himē is chosen for a NASA mission to save the Earth from a comet barreling towards it.

This volume begins the "Death Busters" story arc, or the Sailor Moon S series for those watching at home.  A new enemy is on the horizon, which means the hard-fought peace after dealing with Black Moon is over.  The enemy seems to be centered around the Mugen Academy built upon a triangle of reclaimed land in Tokyo Bay.  At the center of it all is an elite private school that attracts talented students, like violin virtuoso Michiru Kaiō, or the star race car driver, Haruka Tenō (spelled Ten'ô in this translation).  Both have frequent run ins with Usagi and Mamoru, and seem to know more about the new enemy than they let on.  Chibi-Usa makes a new friend, Hotaru, whose father runs the Mugen Academy and has been known to conduct questionable genetic experiments.  Later, the Outer Sailor Guardians make their first appearance, but it's not the happy team-building moment that Usagi wishes it was!

Volume four gives us the resolution of the Black Moon story arc and introduces us to a pretty interesting character: Black Lady, the awakened adult form of Chibi Usa.  Black Lady is the Queen of Darkness, one of Wiseman's most precious warriors, and she is determined to steal the Mystical Silver Crystal of the past and present from Sailor Moon and Neo Queen Serenity.  She plans on doing this by launching several more monoliths of Black Beguiling Crystal into the planet's surface, something Prince Demand warms could destroy the Earth.  Black Lady also captures Tuxedo Mask and makes him fight against Sailor Moon, something that nearly causes Sailor Moon to give up.  But the power of the Mystical Silver Crystal protects the Earth and the Crystal Palace with the slumbering Neo Queen Serenity and the other Moon Kingdom warriors inside. It takes all that Sailor Moon has, and some sacrifices from other Sailor Soldiers, to bring Wiseman to task.

Effie is dropped on her aunt's doorstep in the middle of the night after her mother passes away, and at first, the two can't stand each other.  Selimene believes there has to be some sort of mistake, that an old lady like her can't possibly look after a young child.  Selimene's housemate, Carlota, warms to Effie instantly, and tries to make her comfortable.  Effie starts school and makes some new friends, and eventually she and Selimene begin to get along.  There is something strange about Selimene and Carlota, who claim to be herbalists and acupuncturists.  Effie finally gets the full picture about her aunt's strange life when her magical powers begin to awaken, and Selimene and Carlota reveal they are witches! The three must cure a mysterious curse that is affecting one of Effie's idols, singer Tily Shoo, who is nothing like Effie imagined! 

Volume three is the start of the next story arc. In this portion of the story, the members of the Black Moon are trying to steal the Mystical Silver Crystal, and they’re after Chibi-usa, a strange girl who literally fell out of the sky and demanded Usagi’s Crystal.  Chibi-usa pledges not to let Usagi out of her sight until she has the crystal, so she casts a spell over Usagi's family and moves in as a "cousin" of the family. The Black Moon pick off the Sailor Scouts one by one and weaken Usagi’s confidence in herself and her team.  Towards the end, Chibi-usa finally opens up and reveals who she is, where her "home" is, and why the Black Moon is after her.

The five sailor scouts are finally all together, just in time for the Dark Kingdom, headed by the evil Queen Metalia and Queen Beryl, to start tearing them apart. Kunzite steals Tuxedo Mask away from them just as they all regain their memories of their past lives in the Moon Kingdom. The group finally finds their lost Moon Princess, and they must protect her from the Dark Kingdom. ​ A trip to the moon helps shed some light on who the enemy is and how it impacted their former lives.