Complex sentence: The ova follows Kouji Kabuto, Tetsuya Tsurugi and the rest of the "Mazinger Team" as they fight against Dr. Hell's Mechanical Beasts while Kouji stumbles upon a forgotten laboratory where he finds Mazinkaiser, the most powerful robot ever built.
Split into simpler sentences: The ova follows Kouji Kabuto, Tetsuya Tsurugi and the rest of the "Mazinger Team" as they fight against Dr. Hell's Mechanical Beasts while Kouji stumbles upon a forgotten laboratory. Inside, he finds Mazinkaiser, the most powerful robot ever built.