Hoshigaoka is one of four high school girls dispatched 6000 years into the future to evade human extinction, originating from a present trapped in an endlessly repeating day. She possesses ochre hair and green eyes. Her designated role among the time travelers is verifying their arrival in the correct era using a specialized device called a time measurer, though this device malfunctions. She insists on the title "Time Scripter" for this responsibility. During the mission, her attention drifts from her primary task as she becomes preoccupied with finding sustenance within the desolate future landscape.