Umi Monogatari

Marin and Urin are sea folk, people who live in the ocean. One day, a ring falls from the "sky" - that strange place above the water - and the two girls decide to find its owner. But while the surface holds many wonders, it also hides a great darkness..

Something dark and sinister was released from that stone coffin. Rain is pouring down, the seas are churning, and... a turtle statue just came to life?! His name is Matsumoto, and he knows the truth behind what's happening.

Since Marin has a newfound duty as Priestess of the Sea, she'll need a place to stay. What better place than Kanon's house? Kanon thinks it's the worst idea she's ever heard; but as for Marin, this is the perfect chance to learn more about her new friend.

Kanon needs to be 100 percent pure, but right now, she's way too evil. So, to help her in her quest for purity, Matsumoto gives her a treasure map. If she can find the mysterious treasure hidden on Kagero Island, it will grant her the pure heart she seeks.

A solar eclipse is coming, but while it should be a happy event, Matsumoto has a dire warning. If Kanon finds her heart drawn to darkness during the eclipse, she might lose her ability to become a Priestess. Marin vows to protect her, no matter what!

Everything is falling apart. Urin is missing... The sky is black... Marin can't shake the cold grip on her heart... Ghostly purple butterflies are swarming over the sea... And the eclipse, that blood-red ring in the sky, continues on without end

Urin has returned to the sea, but something's not right. Ever since the eclipse, Urin has been cold and distant... Marin rushes back to the sea as well, but Kanon can't follow. She needs to find a way to breathe underwater – she needs the Ortelius Ring!

Marin and Urin used to be inseparable. Where one would go, the other would always follow. But now, Urin is walled off and locked away, beyond Marin's reach. Is this what Urin really wants? Will they ever see each other again?

Marin is so filled with doubt and grief, that she can no longer become the Priestess of the Sea. Her only hope is Kanon, the girl who has always carried darkness in her heart, yet still found a way to become the Priestess of the Sky. What is her secret?

As Sedna's power grows, a haze spreads out from the sea and covers the town. Even though Marin and Kanon have gotten stronger, they're no match for the darkness seeping its way into everyone's hearts. Kojima, Suzuki, Miyako... no one is safe.

Things are only getting worse... Not only are the people on land under Sedna's control, but so are the people of the sea – including Warin and Sam! They climb out onto the shore, armed with weapons and ready to fight. A terrible battle is about to begin!

The truth behind Sedna's identity has been revealed, but it's too late. The Bermuda Stones are shattered, and Urin has been completely changed, taking on Sedna's physical form. In the suffocating darkness, is there any hope left for the light?