Reclaim the power of your backside! Three popular voice actors, Takuya Eguchi, Kotaro Nishiyama, and Chiaki Kobayashi, take on the forbidden butt battle!! When Phantom Thief Siri Prince suddenly appears at the Kindan Shiri Radio 10th Anniversary Party venue, popular voice actors including Takuya Eguchi, Kotaro Nishiyama, and Chiaki Kobayashi, along with over 1,000 shiri-jin (butt fans), find themselves imprisoned in the butt dungeon! The fierce battle for freedom begins!! Who will reclaim their butt power and survive? [Included content] - Variety Corner: The cast and confined shiri-jin take on challenges issued by phantom thief Siriprincess as they compete for 10 billion units of butt power through various games! - Radio Corner: The iconic segment from Kindan Shiri Radio, Shiri Chiebukuro, was performed live for the shiri-jin gathered at the venue. - Reading Corner: Day and night performances with different content! The afternoon show featured a suspense-style story starting when an unexpected person appeared before the two on their way home after the Kindan Shiri Radio broadcast in November 2017, while the evening show delivered the Kindan Shiri fairy tale "Urashiri Taro" performed by the full KINDAN SIRI Xtreme cast. [Cast] Takuya Eguchi / Kotaro Nishiyama / Chiaki Kobayashi