In a world where humans coexist with androids called Neans, a group known as the Immortal Nine rises up against society. Tasked with disposing of the revolters, a Nean named Rouge Redstar (aka Metal Rouge) and investigator Naomi Orthmann head to Mars to track them down…but first, Rouge wants some chocolate.

Having just moved from Tokyo to Hokkaido, high school student Tsubasa Shiki decides to explore the picturesque winter landscape he could never experience in the nation's capital. It only takes a moment for Tsubasa's idealized view of Japan's northernmost prefecture to crumble, as the sheer cold and frigid air quickly overwhelm him. While trying to find the way to his new home, Tsubasa runs into Minami Fuyuki—a talkative and friendly Hokkaido native who, despite the cold, is wearing a short skirt. The girl wastes no time in striking up a conversation, and Tsubasa comes to realize that the winter weather is not all that is too much for him to handle. The next day, Tsubasa is shocked to learn that not only is Fuyuki in his class, but her seat is also right next to his. Swept along by Fuyuki's persistent advances, the young man soon becomes captivated by both life in Hokkaido and the beautiful girl determined to get closer to him. As he deepens his relationship with Fuyuki and meets other fashionable girls from his school, Tsubasa finds out that Hokkaido gals truly are adorable.

Satou has been in love with his childhood friend and neighbor, Hime, ever since she and her grandfather appeared out of nowhere 10 years ago. Now a dazzling, yet mysterious high school beauty, she makes it more and more difficult for him to confess his feelings. As the anniversary of their first meeting is nearing, will he muster up his courage to transform their friendship into something more? Or will an entirely different fate await this tightly bonded pair?