In Heart Forth, Alicia, players take the role of a young wizard named Alicia, a woman raised in the magical village of Brenia on the sky island Auster. Half a century ago, the Spirits cursed Brenia, and since that day no children have been born save two: Alicia, and her best friend Hostra.
On the day of their Trial, the coming of age ceremony for youths in Brenia, one of the Spirits returns and wreaks havoc within their village. When the two young wizards attempt to flee to safety, Hostra comes under the spell of the Spirit and tosses Alicia from the island and into the Void below. As she fades away into the nothingness, Hostra returns to the village, slowly destroying it and its inhabitants.
When Alicia awakens on solid ground, alive and well and certainly not lost in nothingness, she discovers something she had never imagined: a whole world lay beneath the clouds. Lost in a strange new land, Alicia sets out to find the means to return to her village and the power to save it.