An animated adaptation of episodes 1-3 (out of 6) of the popular Japanese MMO, Phantasy Star Online 2.

ARKS is an organization made up of three races: the dependable humans, the Photon-wielding Newmans, and the powerful man-made constructs called CASTS. The three work together to fight against the Falspawn, a primordial evil created from a mysterious entity called Dark Falz. A team of rookie ARKS members go on a mission to the planet Naverius, which is supposed to have no Falspawn, but a sudden attack leaves only two survivors: two young men named Ash and Afin. The two witness a young woman falling from the sky, who seems to remember nothing but Ash's name, despite the two never having met before, and her own, Matoi. Ash is then contacted by a mysterious entity only he can see named Xion, who starts giving him advice on the future. Ash, Afin, and Matoi thus set out on an adventure that will not only reveal the truth behind Dark Falz, Matoi, and Xion, but shake the very foundations of ARKS itself.