Adaptation of episodes 1–3 of the 5 total episodes from the Phantasy Star Online 2 game along with original content.

Episode 1: During their qualification exam in planet Naberius, the player and fellow ARKS trainee Afin were attacked by vile organisms known as Darkers. This is followed by the two discovering a mysterious girl who lost most of her memories, and the truth regarding Naberius and the recent spike of Darker activities.

Episode 2: The plot follows the player and Matoi as they try to unravel a dark conspiracy regarding the origin and purpose of ARKS.

Episode 3: The discovery of the planet Harukotan brought a new quest into the fray, as the peace between the Shironian and Kuronites that dwell in the planet is disturbed by the Kuronites' sudden attack. The newly-reformed ARKS is tasked to investigate the reason behind it all, and it seems like the truth is more complicated and horrifying than expected...

[Source: phantasystar.fandom.com]