Shichinin no Nana

Japanese Title: 七人のナナ

English Title: Seven of Seven

Plot
After seeing a Rainbow rainbow as a child and being mesmerized by its beauty, Nana's grandfather has been trying all his life to capture the beauty of a rainbow within a crystallized form. After years of failed attempts and crazy inventions, such as a VCR toaster and vacuum cleaning mouse catcher, he finally discovers a way to make such a crystallized rainbow. His plan would work by separating the light from a rainbow into its seven basic colors and then reforming it into seven colorized crystals. His experiment was working too and only needed a few seconds in the microwave to be complete and finally fulfill his dream. That is when Nana, who was searching for the microwave in an attempt to bake a chocolate cake for Yuichi, opened the door before the crystal had fully hardened and caused an accident.

The crystal glowed and split into the seven colors of the rainbow, hitting Nana as one color and coming out of her in seven separate colors of the rainbow, creating seven different Nanas. Aspect of Nana's personality suddenly exist its own separate physical form, there is a giggly Nana, a sleepy Nana, a crybaby Nana, a grumpy Nana, one who is a bit of a flirt, and an intellectual Nana, who all standing alongside the original Nana. However, they are all also the same Nana, and all share the same feelings for the boy Yuichi, which is clearly seen as their first thought is to finally make that chocolate cake which they try to do and are working and talking in perfect sync with each other, as if they were still just one person, that is until the cake is done at which time they start fighting over who will give it to Yuichi.

Each Nana grabs one of the crystals that formed from the one crystal her Grandfather was trying to harden in the microwave and realizes it gives her super powers, she can fly, has super strength and super speed. This leads to a chase between the original Nana, and the new six sides of her personality who are all fighting as they fly and destroy parts of town over who will give the cake to Yuichi. When they finally finish, they once again prove they are all parts of the same Nana as they are all too scared to approach him and hand him the cake.

The crystals also hold another power seen later on as Nana wears a costume from an anime she (and the other Nanas) loved as a child called the "Nana Rangers". While they are wearing the costume and at the same time carrying their crystals the prop costumes turn into the real "Nana Rangers" costumes allowing them at times to be Superheroes, and also all show themselves in public at once, since Nana and the others realize the danger of all being seen at the same time without masks or some way of hiding that they are all the same person.

After they had settled on their roles, the 7 Nanas also face the fact that if the crystals are not reintegrated within a year after the split, all 7 of them will disappear. Later, the 8th one appears causing chaos.