You're a 14-year-old girl who just watched your grandfather's invention go haywire and summon an alien threat nobody prepared you for. Now you're merging bodies with your friends to fight it, and the show treats that intimacy like it matters as much as the actual combat. The transformation sequences aren't there to titillate you into submission, they're the show asking what it means to be vulnerable with people you trust when the world ends. This is a magical girl show that actually understands why the magical girl formula works at all: it's not about the power, it's about the girl you become when you're not alone.

Fourteen-year-old Akane lives a modest but contented life on Ooshima with her dependable younger sister Momo, who handles the housework, and their grandfather, an inventor whose gadgets mostly turn out useless. From their island they can see Blue Island, home of the Manifestation Engine, a revolutionary technology that solved the world's energy problems. That peace breaks when mysterious beings called the Alone appear and go after the Engine. Ordinary weapons fail against them, so Akane's grandfather gives her a special key that only she can use. With the Vivid System it turns her into a powerful red-armored heroine. Aoi, Wakaba and Himawari soon join her, and the friendship between the girls becomes humanity's last hope. The result is a sci-fi magical girl action series with an ecchi streak.