This anime OVA told the same story as Magic Knight Rayearth series but with a few different character design. The Story is a synopsis of the series from beginning until the final battle between the magic knights, Princess Emerald and Zagato. Zagato is the person who kidnapped and captured Princess Emerald. The ending is a battle of the giant mecha (robot). If you want to know the story after the battle you could watch the Magic Knights Rayearth series. Personally I don’t like the OVA but I like the series and the Manga (Japanese Comic).