OVAs
(often interchanged to OAV) stand for Original Video Animation. It's basically
how the Japanese refer to anime that goes straight-to-video. OVAs are
episodes usually from 30 to 60 minutes long that offer higher production
values than TV animation, yet they aren't movies. The two OVAs were the first pieces of animation released for the Mermaid Saga, though both pieces have very differing looks from one another due to the different companies involved in each. The first OVA, Mermaid Forest was handled by Studio Pierrot and Victor Entertainment, while it's sequel, Mermaid's Scar was animated by Madhouse.
Both OVAs were adapted into English in North America shortly after they were made. U.S. Manga Corp released a subtitle-only VHS of Mermaid's Forest, marketing it with their "Rumic World" releases of Maris the Supergirl, Firetripper, and The Laughing Target. Meanwhile Viz Media (then known as Viz Video) released Mermaid's Scar as a English-dub only VHS as one of their very first anime releases. Unfortunately both companies have allowed the Mermaid Saga OVAs to fall out of print.
The story begins by setting up the story and showing Yuta's immortality. In the 1980s he and Mana encounter the mysterious white-haired Towa, who wants Mana's body for her own. It seems Towa too is immortal, though her attempt was not as successful as our protagonists.
Mana and Yuta meet a little boy named Masato while travelling on a train. The boy is being reunited with his mother who seems cold and distant. Soon Yuta and Mana realize that both the boy and his mother are immortal, but things are not quite as they seem between the gentle Masato and his cruel mother Misa.
The themes are Tears of Eternity by Akino Arai & Beads of Tears by Maki Mochida.
Kumiko Takahashi (no relation to Rumiko Takahashi) has worked on various other Rumiko Takahashi anime projects including working as the key animator on Urusei Yatsuramovie 4 and movie 5, character designs for movie 6 and animation director on Inuyashaepisode 140.