Mugen no Ryvius

In the year 2225, Kouji Aiba and Aoi Housen are among trainee astronauts stationed at Liebe Delta, situated near the Geduld Sea. During a standard dive operation, the station is attacked by unidentified saboteurs, causing it to crash into the Geduld, a plasma field that connects planets and destroys anything that enters too deeply. All adult crew members are killed, leaving the young astronauts to endure the perilous return journey while dealing with rising tensions among themselves. The saboteurs remain in the background, observing and planning another assault.