Episode One of the OVA follows the manga's first Volume [3]. It covers Seras being turned into a vampire, the introduction of the characters, and the first fight with father Alexander Anderson [3]. There are some minor departures from the manga, such as inclusion of Seras' dream sequence with subtle Chibi aspects[4], and inclusion of Seras being welcomed by Integral, Walter, and Alucard (after the dream sequence she woke up to see Alucard by her side). These departures are not as important as the departures in the TV series. It should be noted that the OVA series returns most of the humor, which was minimal to non-existent in the TV series.
Episode Two of the OVA follows the manga's second volume. Dealing with the Valentine Brothers' assault on Hellsing's headquarters [5]. It is slightly different, as Alucard's battle with Luke Valentine is extended, and there are a few scenes of the brothers individually killing Hellsing soldiers that were not in the manga [6]. The last two chapters of the manga are also left out, probably since the entire episode is heavily action based, although they are seen as images during the credits. Omissions include the introduction of Pip, and Enrico Maxwell with Anderson. The Omake which premieres in volume 2 of the manga is also left out, which likely means it will not be seen in animated form.
Episode Three of the OVA will follow the events shortly after where the credits of Hellsing Ultimate II ended. The meeting between Hellsing and Iscariot, the introduction of the Wild Geese mercenaries, Alucard and Walter's discussion about Millennium, Seras and Pip's argument, the move to the Hotel Rio, The Slaughter at the Hotel Rio, and the Duel between Alucard and Alhambra. The third OVA was scheduled for release in Japan on February 9th, but has since been delayed. The new release date for Hellsing OVA 3 is now April 4, 2007.