Alis is a young girl whose brother Nero was brutally killed by a mysterious man known as Lassic. Nero's last words were: "Sister, find a warrior named Odin, he can help you to defeat Lassic!" Now Alis' dangerous adventure begins. Her first task is to find Odin. Then, with help and support from her friends, Alis will have to stop the evil Lassic and save the world...

This game is the very first installment in the long-lived Phantasy Star series. It is a futuristic RPG that uses a turn-based combat system (viewed from first-person perspective). An unusual feature of this game is that some locations are also viewed from first-person perspective. You can explore those locations by moving forward or backward, and the environments are in pseudo-3D.