Two thousand years ago, humans were protected by benevolent gods and lived peacefully alongside them. However, human green and pride put an end to the paradise-like existence. Humans wished to become like gods, and started fighting them, which led to a prolonged war that darkened their spirits and further corrupted them.
Prominent figures within the leadership of the Republic of Seven Lords are involved in dealings with a mysterious organization. Elluard von Heinberg, the heir of an aristocratic family, is determined to get to the bottom of the political intrigues. Meanwhile, in a quiet village in South Varensia, a boy named Sizz Flair decides to leave his drunken father behind and embark on an adventure with his childhood friend Maria. The two inadvertently draw the attention of the mighty church, and become involved in the grand schemes of the higher powers.
Arcturus is a Korean-made role-playing game in Japanese style, similar to Grandia II in visual presentation. The player can choose between two prologues chapters (either Elluard's or Sizz's), after which the two stories converge. There is no overworld in the game, and areas are interconnected. Battles take place in the same environment as exploration, and are turn-based. The player can navigate characters on the battle field and also take their speed rankings into account, as executions of attacks and other moves depends on them.
Magic can be learned by certain characters and is divided into four elements: Water, Air, Earth, and Fire. Casting spells requires a certain amount of real time when in combat. Characters learn new spells by repeatedly using available ones in the correspondent category. Those who do not have access to magic can execute various special attacks with their own separate point gauges. In addition to HP, characters also have "barrier points", which are reduced first when enemies damage them.