Riku and his friends venture to the city of Perisia, where Gunpla builders display their prized works and exchange techniques with other Divers. Upon their arrival, they learn of the presence of Shahryar, a top Gunpla builder in GBN. A group of Mass-Divers arrive in the city, pretending to be Shahryar, but a masked female Diver named Ayame quickly calls them out as imposters attempting to steal customization techniques from other Divers. Later, Riku and his friends spot the imposters' Xamdrag leaving the city with an unconscious Ayame. As they did not bring their Gunpla local builder lends them his Ptolemaios to go after the Mass-Divers...