Agent Aika is an odd OVA series. Where visuals are concerned, the production values are remarkably high with slick, vibrant animation that still holds up well today. Unfortunately, with all that effort given to the aesthetic design, the creators of the show forgot to include much in the way of character or plot.
Agent Aika follows the story of Aika Sumeragi, a salvager in near-future Tokyo where an earthquake has left much of the city underwater. The entire seven episode OVA series is broken up into two story arcs, the first finds Aika pitted against a madman who wants to wipe out humanity and re-seed the planet with his own "superior" progeny. The second story (filling out the last three episodes) centers on a group of women who had previously been employed by the villain from the first arc, who are now after Aika for revenge.
Pure fan service galore is the only way to fittingly describe Agent Aika. Little more than seconds pass at a time before a panty shot flashes on screen, or until a helpless female is left in a compromising positions (usually tied up or, at the least, left unconscious with their butts poking up into the air).
I'm not against fan service, but Agent Aika's plot isn't very engaging and, worse yet, the characters are so mysterious and underdeveloped, even Aika, that we never get a feel for any of the protagonists. Oftentimes, it feels like the show's creators just made a checklist of everything they wanted included in the OVA and, plot or character be damned, they were going to fit it all in. For instance, Aika is an underwater salvager, but apparently she's also a secret agent, and she has some kind of special bustier made out a material called "ultranate" that can transform her into a nigh-invincible fighting badass with tanned-skin and purple hair. That's about as deep as any character development ever gets, and when characters reference events from the undisclosed past, the viewer is left wondering if they missed something, or if Agent Aika is a sequel to another anime...but it isn't!
Only when the action kicks into gear does Agent Aika shine, allowing the audience to put their minds on autopilot and go with the flow. But even with the fluid, expertly animated battle sequences, it feels hollow due to the lackluster characters.
The studio behind Agent Aika, Studio Fantasia, was also responsible for Project A-ko 3: Cinderella Rhapsody, Project A-ko the Versus, and Megami Paradise, along with two other Aika OVA series. In 2001, Studio Fantastia released Najica Blitz Tactics which borrowed extensively from the premise of Agent Aika, in terms of a near-future setting, female secret agent, and copious amounts of fan service. Najica Blitz Tactics, though far from a masterpiece, improved on the Agent Aika formula in nearly every way. While Najica wasn't a deep character, she at least had some substance to her.
Agent Aika was release in Japan between 1997 and 1999. US Manga Corps released the OVA in North America with an English dub in 2001, splitting the series into two DVDs, titled Naked Missions and Final Battle. Bandai re-released the complete OVA on DVD as part of their Anime Legends line in 2008. The Anime Legends is notable for including a previously unreleased live-action Aika episode. The episode is strange in its own right, but there's also a short "making of" segment too, which is humorous to watch as the director, primarily concerned about his panty shots, makes sure the actresses protrude their butts just right for the camera!
Studio Fantastia returned to Aika in 2007 with a prequel series titled Aika R-16: Virgin Mission (also released by Bandai in the US) and revisited the buxom agent once more in 2009 with Aika Zero (which didn't get licensed in the US).