1. Secret Game

Aika Sumeragi, a high school age C-Class salvager, is hired by class president Eri Shinkai to pilot her salvaging vessel. After introducing Aika to the treasure hunting club, and revealing coordinates hidden in a marking on fellow classmate Karen Minamino's chest, they embark on an adventure to see where it leads.

2. Peach Peach Beach

3. Deep Blue Girl

In the final episode of the series, Aika, Eri, and Karen find an old airport at the bottom of the ocean. After exploring the still functional facility, they finally uncover the secret to Karen's past.