Project A-ko 4
Final
Here is the official blurb from the back of the cassette:
All A-ko Magami wanted was a simple life, to study hard, to pass her exams, and have some fun with her cute-yet-bubbleheaded pal C-ko Kotobuki. But nothing is ever simple when you're the strongest schoolgirl on earth with an alien princess as your best friend, and when local rich girl and school bully B-ko Daitokuji decides to bust up A-ko and C-ko's friendship, high explosive hi-jinx, mecha mayhem and a whole lot of collateral damage are never far away...
In an ancient tomb, archaeologists discover a strange hexagram symbol lit with an unearthly power. Meanwhile in Graviton City, schoolteacher Miss Ayumi studies the same pattern on her necklace, and at the edge of the solar system, thousands of starships emblazoned with the symbol are on an interception course with Earth.
While A-ko and B-ko continue their fist fight feud over the friendghip of C-ko, Miss Ayumi begins to feel her age so B-ko's dad sets her up an arranged marriage with Kei, the gorgeous biker who pines for C-ko but has captured the hearts of A-ko and B-ko! With the colossal alien starfleet cruising ever closer, and Ayumi's behaviour becoming stranger by the minute, It's One Wedding And An Alien Invasion as the FINAL chapter of the Project A-ko saga comes to an earth shattering climax!
Miss Ayumi has no special power, she is not connected to the alien fleet in any way. Her necklace is just a trinket, a good luck charm that's supposed to help her find love.
The wedding is interrupted by A-ko and B-ko, and then the alien starfleet. Miss Ayumi dosen't marry Kei after all, she drops him, literally, when he pines for C-ko.
The connection between the hexagram in the ruins and the Alpha Cygan Starfleet is probably a co-incidence, as surmised by the head archeologist. (His peers don't share this theory, and brain him with mallets!)
C-ko departs with the alien fleet, but returns the next day to be with A-ko.