The Space Pirates, using Metroids capable of possessing a host, attack a Federation facility on Tanamaar which recently unearthed an artifact. Samus is dispatched by the Galatic Federation to prevent the Pirates from stealing it. The Pirates are being led by Sylux, a rogue hunter whom Samus had previously encountered. In the confrontation with him, Sylux accidentally damages the artifact, causing it to activate and teleport everything in its surroundings to the unknown planet of Viewros.