The main premise of this anime is set in a futuristic world where Japan is mostly submerged and the
seas have become a dangerous place for the Japanese. At such a time, a group called Blue Mermaids is formed, which takes on a role similar to the navy and they safeguard the seas surrounding Japan. The main cast is a group of drop-outs with the worst grades in the cohort aspiring to be Blue Mermaids, and they are assigned to the ship Harekaze.
At first glance, this is similar to any average slice-of-life story with a group of girls living to their fullest on a badly-equipped ship as they struggle to catch up with their other more capable peers in the cohort. However, there is a deeper malice in this series which was revealed in the very first episode in the form of a rebellion, where the main cast were instantly framed and became wanted criminals for being rebels.
The art is pretty average as compared to most of the series released during this season and over the past year. There isn't much setting it apart from other "cute" anime styles. Though, I would like to applaud the bright use of 3D CGI for the ships which still manage to allow them to move smoothly and realistically and actually improves on the anime instead of holding it back.
The opening and ending themes for Hai-furi are catchy and I absolutely love how the opening theme sound, so much so that I have ordered the CD for it. However, there are certain occasions where the OST fails to match the intensity of the anime, such as a battle scene between warships accompanied by a cheerful tune just does not cut it for me.
There are many girls in this series, mainly to fill up most of the positions on the ships. To be honest, I never knew there were so many positions before watching this anime. Most of them have a basic sculpt to their personality albeit mostly falling into cliches, for instance, the silent and nearly always expressionless girl, the overly-dramatic girl who loves acting, one who lusts over action and echoes for the usage of firepower against enemies whenever a chance arises, and a scaredy-cat who doesn't want the ship to approach any danger. None of the girls have fully developed personalities and backstories so far in 4 episodes though. As there are many characters, I would be covering the main three in this story.
I must mention here that though I am trying to be impartial, I do favor Misaki Akeno a lot out of all the characters in this series. She is the captain of Harekaze hence considered the leader of the main cast. Despite having bad grades, she has displayed extreme tenacity when the time calls for it. Such is when Harukaze was under attack and she made swift judgments to effectively counter the attacks dealt at them, despite being on board a much slower and badly-equipped ship. Though, Mike-chan (her nickname given by her childhood friend, China Moeka) is probably not a girl for everyone as she puts her family (the crew on board of Harekaze before anyone else and for individuals who can't stand those types, they probably can't stand her either.
Munetani Mashiro is the vice-captain on board of Harekaze and she is troubled by her constant lack of luck. This was depicted by how she got all the answers right in the examination, but filled in her answers off by a row, thus she ended up being on the lowest-tiered ship instead of the best ship, Musashi. Mashiro is a prideful tsundere character and while she doesn't accept Misaki as the captain at the beginning, she grows to accept her as more battles pass with Misaki showing her quick thinking and flexibility.
China Moeka, otherwise known as Moka-chan by Misaki, is an gentle honor student who is the captain of Musashi, the best ship in the school. She doesn't have much development beyond that as the story has been focusing on Harekaze mainly and not much information about other ships are available, let alone the crew on them.
This anime is quite effective as a relaxing anime that keeps you in suspense. That being said, it isn't a good choice if you are an impatient person wanting to find out more about the story as the revealing of the dark secrets the story is spun around is being revealed very slowly. Despite being in episode 4, the story still adds these suspense elements to itself while not unveiling the truth behind most of those presented in earlier episodes.
For instance, Musashi sent a call for help which was received by Harekaze at the end of episode 2, yet even until now, there is no word on what happened to Musashi or Moeka. Instead, they merely proposed a possibility that a red-eyed rodent rat that made its way on to Harekaze might have something to do with the rebellions as contact of the rodent with a Harekaze member, Shima Tateishi, caused her to be possessed, hence it was postulated that this might have some relation with the mind-controlled crew on other ships.
From Your Fellow Anime Fan