The plot in Xenoglossia regards the destruction of the moon several decades ago and the devestation it’s lack of gravitational pull has had on the planets tides and overall ecosystem stability. Making thing worse are the fragments of the “Lost Artemis” that frequently fall to Earth, bringing yet more destruction in their wake. In order to combat this the organization Mondenkind has deployed five idols built around very powerful harmonically tuned cores found in the wake of the moons destruction. Piloting these giant robot idols are iDOLM@STER’s who must be female in order for the idols to allow control. These idols are then deployed during meteor showers and used to destroy large asteroids with high powered sonic shockwaves emitted via a nicely delivered punch. Making Mondenkind’s trouble worse is the organization Turiavita, which seeks to steal away all the idols from Mondenkind and it’s iDOLM@STER’s and allow the destruction of humanity to occur so it’s own touted superior genetically engineered race of Idol/Human hybrid called the Mischling’s can take over in it’s place. Much of the series is about the battle between Mondenkind and Turiavita for control of the idol’s as well as the shifting bonds and rivalries between the iDOLM@STER’s themselves.