The game takes place on either an island or a seaside town; lack of AGTH support for now hampered my understanding of things. The characters are as follows:
Emoto Aki
The male protagonist. Not too much to say about him. Basically your typical male protagonist, but with glasses, and an inability to swim.
Asanagi Mio
Main heroine, the redhead. Her true form is that of a mermaid, and she switches to that form when she gets doused with water. She relies on a magical mermaid hammer to transform herself into a human, and it's with this hammer that she erases the memories of people who happen to see her true form. She's kinda popular around the school, and is also in a music or singing club of some sort. She has a straightforward and blunt personality, and fits into the tsundere category, and since she's a sort of princess in the mermaid world, she's kind of an ojousama too. She's also in the same class as Aki, but the two haven't really interacted until the start of this story.
Takanashi Miyuki
I'm running down Getchu's character list so she is the blondish girl with the whale ornament in her hair. She's Mio's friend, one year under Aki and Mio, and obviously totally in love with Aki, who's totally dense in return. She makes a bento almost daily for her senpai and tries to hang out with him when possible. Those experienced with ero games know that type of girl I'm talking about.
Emoto Yuriko
Aki's older twin sister, who is in a different class. A boisterous and energetic personality, frequently doting on her brother and teasing him about his choice in friends, his lack of a love life, his indulgence in the occasional ero-game, and other things. Judging from her profile, apparently possessive of him as well (If any girl wants a hand at my brother, she has to get through me first!! or something like that). Has great proportions (
), and currently the #1 ranked character on a poll on the official website. My favorite character as well so far.
Shiratama Kanaka
A mysterious girl in traditional Japanese garb who roams the city. Aki meets her one day when she eating an ice cream and the wind knocks it over. Aki buys her another one, and their interaction starts from then. The trial doesn't reveal much else about her.
Mariel Livingstone
Aki's classmate with whom Aki is friends with and chats often. Cute in that sort of small child sort of way kind of. Not much more of an impression of her at the moment.
Emoto Himawari
Aki and Yuriko's mother, and a miko (or the owner I think) of the shrine, where she and her two children live. A bit of an air-head and over-protective of her children, throwing a worriesome fit when they come home ten minutes late.
And I have a feeling that she can't cook.
Takamoto Souchirou
Aki's best friend, sort of. That slightly off dude who's responsible for your family members thinking that you're obsessed with ero-games.
The story:
The trial tells the story so far with a lot of mix-ins of flashbacks and some parts seem as if they're not exactly complete, so I'm going to give a chronological summary.
Yuriko ambushes Aki in his room while he's playing an FPS game (a Japanese FPS gamer!? Hell --> Frozen?? O___O ), and after some teasing, she joins him in the game where she somehow beats him every single time. In the last match, she makes a bet: beat her and she'll strip however much Aki wants her to. If he loses, he has to go buy her a drink. So he loses and goes to get the drinks.
On the way back he happens to pass the beach where he catches Mio singing. A gust of wind blows and lifts her skirt to reveal no pantsu. Mio spots Aki, and Aki falls into the ocean in a panic. When he regains consciousness he's somehow back on the beach and alive.
The next morning at school, Mio calls him out to a secluded area in the school and asks him if he remembers what happened. You can offer either a yes or a no at this point, but in either case she materializes that hammer of hers and manages to strike him in the head with it.
He wakes up in a nurse's office with Mio going on about how he fainted in class.... and then changes it to how he fainted in the courtyard, and about how she found him unconscious and he had to be carried to the infirmary. Aki feels there's something wrong with all this and briefly remembers her clonking him on the head with her hammer out in the courtyard but says nothing about it after Miyuki suddenly comes in gushing about her sempai being okay and unhurt and such.
Mio has a feeling that Aki remembers something so she stalks him the next day after school as he hangs out with Souchirou. Some time after, Mio confronts him in her clubroom and finds out that he does remember. She clobbers him with her hammer again.... and nothing happens. She's surprised, and then angry, and demands that Aki let her clobber him some more. The struggle moves into one corner of the classroom where they accidentally tip over a bucket of water......
and then:
As Mio is crying and lamenting her situation, some people enter the classroom, and Aki carries Mio and jumps out the window, from the second floor, into the pool below (shallow end). He then carries her all the way out to a secluded beach.
Explanation time happens. Mio explains that her hammer allows her to change into human form and erase people's memories when needed. She demonstrates and is surprised when her human transformation works. She's happy that her hammer's apparently not broken.... or not, when she tries to clobber Aki again and nothing happens.
Mio has Aki promise never to reveal her secret to anyone, but that's not enough. She tells him that he now has to be her 24/7 bodyguard to help keep her secret safe. Dun dun dun!!