The shocking death of the heroic Sheriff Pink at the hands of the evil brothers forces the Cosmic Security Agency to adopt new technology—Neo Boost Mode, a massive evolution of the original Boost Mode. While this advanced system drastically enhances performance, it also places an even greater physical strain on the user. Manami Kishigaki, the successor known as Sheriff Yellow, reluctantly accepts the new system and sets out on a mission to pursue a new wave of cosmic criminals. However, a mysterious and powerful enemy soon appears, pushing her into a desperate battle. Cornered and overwhelmed, Sheriff Yellow activates Neo Boost Mode in desperation and manages to defeat her foe—but at a terrible cost, suffering intense physical pain from the backlash. Days later, the elder of the supposedly dead evil brothers suddenly reappears before her. Confused and wary, she begins to uncover his true identity. Can Sheriff Yellow finally defeat the evil brothers and avenge her fallen comrade?