In Metroid Prime Hunters, what cluster sends the mysterious message Samus investigates?

In Metroid Prime Hunters, the mysterious message Samus investigates is sent from the Alimbic Cluster.

The Galactic Federation receives a telepathic transmission declaring that the key to an “ultimate power” lies somewhere in the Alimbic Cluster. The Federation asks Samus to investigate, but the broadcast is also intercepted by six rival bounty hunters, who travel there seeking the same prize. This setup makes the cluster the game’s central setting and the source of its mystery.

The Alimbic Cluster lies in the Tetra Galaxy and includes two planets, Alinos and Arcterra, plus the Celestial Archives and Vesper Defense Outpost. As Samus explores these locations, she uncovers the history of the Alimbic race, which vanished after imprisoning the destructive creature Gorea in the Oubliette.

The message is not simply an invitation from the Alimbic civilization. It is ultimately part of Gorea’s scheme to escape its confinement, adding a major twist to the investigation. Aether belongs to Metroid Prime 2, Orpheon is associated with Metroid Prime, and Vesper is a station within the Alimbic Cluster rather than the message’s originating cluster.