This episode begins with Kojima in danger from two of Sedna’s creatures, the creatures use words that Urin used earlier, and Marin calls to Urin to return to her side, she’s not cruel like this. It seems that Marin’s words do reach Urin and her/Sedna’s creatures release Kojima, and Urin says to herself that her sister loves her, but soon Sedna’s uses words to regain control of Urin. Sedna has Urin release a blast of power that starts to kill and pollute everything it touches, it spreads outwards to engulf the whole ocean, and we see that Urin is released from the power bubble and she’s transformed into a creature filled with dark energy.
As Marin and the crew observe the polluted sea they notice hundreds of Sedna’s creatures approaching the island, and Marin calls forth her powers and purifies all of the creature. The Turtle Elder makes the comment that Marin has gotten stronger, but this action has really drained Marin.
When Kojima reawakens he says terrible things to both Kanon and Marin and storms off on his own, and the Turtle Elder says that it’s easy for Sedna to affect pure hearted people. We also see that Sedna’s influence is starting to affect people such as Suzuki, making them say hateful things. When Ooshima runs into Kojima, she tries to confess to him but he’s so cruel to her that she ends up in tears, and all over the island people are saying hateful things to one another.
Once the crew return to Kanon’s house they find Urin waiting for them by Kanon’s bedroom window where she tells Marin that she’s here to get her, and that now she’ll protect her. Urin asks Marin to come over to her side since light can’t defeat the darkness, and she also tells Kanon that this is her fault by showing Kanon her ring and telling her that her desires summoned Sedna to her. Once Urin knows that Marin won’t return to her she uses her Sedna butterfly wings and flies away from the house.
Later, the Turtle Elder takes Marin and Kanon to the place where Sedna was sealed and explains to them the nature of Sedna and how to reseal her, they must summon the Spear of Radiance and thrust it into the core of Sedna. Since Sedna has taken over Urin’s body this means that Urin will most likely share the same fate as Sedna. Well, both Kanon and Marin aren’t taking this news very well, but the Turtle Elder tells them that it’s either that or let the world fade to darkness.
A few minutes later, Marin tells Kanon that she’s going to take Urin back from Sedna, and if she fails Kanon needs to seal her with Urin. Kanon tells her to calm down, but Marin says that Urin has do nothing wrong other than feel a little lonely and that she should have noticed it happening. Marin says that she won’t have Urin sealed with Sedna, and Kanon vows to Marin that they will find away to save Urin from Sedna, the Turtle Elder says this is very risky.
Later, Kanon takes the crew to a small shrine where it is said that if you pray here the sea will wash away the sorrow. After both Kanon and Marin pray, the island priestess appears before them and she she explains the separation of light and darkness and why they hate and fear one another, and she also says it’s an eternal battle. The Turtle Elder disagrees with her saying we have to fight and win this battle.
Later, on the beach, the Turtle Elder teaches the girls the spell to summon the Spear of Radiance and tells them they have to strike Urin in order to seal Sedna’s powers. Both Kanon and Marin vow to separate Sedna’s powers from Urin before they strike, to which the Turtle Elder says that this is quite a risky idea. While all this is going on, the Turtle Elder’s daughter is snatched by Sedna’s agents while she’s standing near the ocean, and a few seconds later she reappears as a agent of Sedna along with Warin and Sam who have also fallen under Sedna’s spell. Well, that’s all for this episode.
Well, Urin is fully transformed and Marin and Kanon finally are told what must be done to defeat Sedna, and what a terrible toll it’ll be. We’re finally told by the Turtle Elder that Sedna never really had a body until now and this battle has been fought over and over again. What a terrible choice that Marin is given, to defeat Sedna she must most likely kill her beloved little sister who’s hasn’t committed any crime other than becoming lonely. This episode really showcased how deep Marin’s love for her sister goes, she’s willing to sacrifice her life and spend eternity sealed with Sedna, and Urin rather than let her sister be alone forever with Sedna.
I feel that the Turtle Elder is wrong about the current situation and the shrine priestess is right, what she’s trying to tell them is that because the light and darkness are separated they hate and fear one another when the light and darkness should be at peace. I think that the solution to this problem will be like in the fifth season of Sailor Moon after Usagi defeats Sailor Galaxia who harbored Chaos inside her. Usagi was asked if Chaos was destroyed or sealed and she tells them “no” and that the darkness/chaos is where it belongs; All of us have small pieces of the darkness inside our hearts and it’s up to us to keep it in check. So, in affect, we are all creatures of light and darkness, good and evil, order and chaos, and the choice of how we act is up to us.