Monkey D. Luffy's childhood buddy and former Red Hair Pirates musician Uta once made a pledge to the world that she would sing jubilant music to usher in a new era of freedom. At Uta's first-ever live performance, where a large crowd has gathered to take in the diva's unearthly singing, Luffy and the Straw Hat Crew arrive. Uta has a deep-seated loathing of pirates due to a childhood trauma; her joyous reunion with Luffy is shattered when she finds out that he has now turned into one. Due to Luffy's refusal to alter his behavior, Uta uses her abilities against the Straw Hats. The team quickly discovers that while their unconscious bodies remain outside of Uta's dream realm, their minds have been imprisoned inside since the start of the concert In the actual world, asleep. The Straw Hats must find a way out of the nightmare before it's too late or they'll spend all of time in Uta's dream.