Because of their Hamaji Junior High School closing, Umimura residents Sakishima Hikari, Mukaido Manaka, Hiradaira Chisaki, and Isaki Kaname are transfered to Mihama Junior High on the surface.

Hikari thinks of Manaka while he's at home, and decides to tell her how he really feels about her. Manaka also tries to tell him something, but then tells him that she'll tell him as soon as the Ofunehiki is over.

Miuna makes a snow sea slug out of the saltflake snow that had fallen on the surface. Meanwhile, Hikari thinks about how his father is doing alone in the sea. In the sea, Uroko-sama had gathered everyone to tell them of the calamity that was about to come.

Akari is able to tell Uroko-sama and her father how she feels about Itaru, and is starting to smile a little again. Hikari sees that and feels a little better and heads to school. While on their way to school, Chisaki is late and walking on her own.

The day of the Tomoebi, a Hikari who hasn't aged from five years ago, appears in front of Miuna and Tsumugu. He has no memory of what happened since the Ofunehiki, but seems healthy and starts living at the Shiodome household.

Kaname suddenly confesses his feelings to Chisaki in front of her parents, and Chisaki doesn't know what to do. Hikari and Manaka do their best to go on with the Ofunehiki, hearing that if the Sea God gets his powers back, the disaster that is to befall their world may be stopped.

In order to save Manaka, Miuna is swallowed up by the whirpool that Ojoshi-sama made and is covered in Ena that wraps around her like a cocoon. Hikari and Tsumugu go to save her but are held back by the powers of a god.

After school, the classmates get together in the woodshop room for the final stretch of getting the Ojoshi-sama done. After the students finish the Ojoshi-sama, even the teacher gets excited about the feat, and they wonder if it's possible to somehow do an actual Ofunehiki like they used to do with the surface and the sea working together.

To stall the saltflake snow and try to get Manaka's feelings back, Hikari and the others decide to do another Ofunehiki. The day before the festival, after hearing that the red sea slug pendant has Manaka's feelings in it, Akira takes it and accidentally drops it into the sea.

Akari was rounded up by the older men of the village and Hikari and the others try to stop them. It's there that they first hear the rule that if you are seeing someone from the surface, you will be banished from the village. Hikari, unable to contain his rage, holds a guys-only meeting with Kaname. The girls are thrown out and go to another room, where Manaka finds a red-bellied sea slug. The sea slug is said to tell you the future if you tell it feelings you can't tell anyone else. It's then that Chisaki asks Manaka if she likes Tsumugu-kun...

Tsumugu dives into the sea after Chisaki. He starts having trouble breathing and is about to lose consciousness, but then suddenly gains Ena. Tsumugu finally catches up to Chisaki and lets her know his feelings while they're in Shioshishio. Chisaki cries and runs away.

Hikari starts back at Hama Junior High and is in the same class as Miuna and Sayu. He fits right in instantly, making the class laugh and has his old teacher back. But Miuna and Sayu can't help but feel that the situation is weird.

Uroko-sama tells Hikari and Miuna that Manaka has lost the heart to fall in love with anyone. Hikari tries desperately to find a way to turn Manaka back to normal, and has a hard time facing her because of that. Hikari and Miuna decide to talk to Chisaki, Kaname, Tsumugu, and Sayu about the situation because that's how they've always solved things.

Five years has passed since the Ofunehiki and Shioshishio's hibernation. Without knowing how Hikari or Manaka or any of the others are doing, now a 19 year old Chisaki goes to visit Tsumugu's grandfather in the hospital.

Akari makes the decision to take Ojoshi-sama's place in the Ofunehiki and head into to marriage with Itaru like she was headed toward the Sea God. That was when the preparations to try to re-enact the first Ofunehiki went back under way.

Because of Uroko-sama's curse, Manaka ends up with a fish face on her knee. It goes away the next day, but she has some regrets because Tsumugu had said it was pretty. Meanwhile, Hikari gets annoyed that Manaka and Tsumugu are talking and tells him to not concern himself with the people of Umimura.