Gift is a world where glittering blue crystals known as Giftium are buried deep underground. A young boy named Sogo Amagi lives in the prosperous mining town of Garden Indigo. Sogo, whose hobby is collecting rare crystals, one day becomes involved in a dispute between classmates Kaon, Roman, and Otto. He wanders deep into the ruins of a mine and discovers an underground lake. There, Sogo meets a mysterious blue-haired girl with red eyes named Felia and their fateful meeting is the start of a new adventure with their newly formed bond.