Formed in 2009 around violinist Keisuke Takashima, ptf is an instrumental band oriented towards progressive rock/metal. To date, they have released four albums. Despite being an instrumental band, they have released numerous concept albums and suites, and despite being a guitarless band with violin as the main instrument, they aim for a metal sound, building a unique world with a one-of-a-kind sound. This fifth album is a socially conscious album centered around the masterpiece "THESIS," which exceeds 25 minutes in length, with the theme of the fragility inherent in human values. What you believe to be justice can instantly be labeled as evil when seen through the filter of different values. What are values? What is justice? Values, the foundation of society, are multi-faceted and ambiguous, and we entrust ourselves to and contemplate on extremely fragile ground. What is right, what is ideal, and what should we share?