In a future where time travel has become a routine technology, even students use it to supplement their education. The story follows Inochi and Akari, two members of a paleontology research institute who spend their school days journeying into the deep past to investigate ancient organisms. Their travels span a vast expanse of natural history, taking them from the bizarre life forms of the Ediacaran period 600 million years ago all the way to the present day. These field trips are not merely observational; the girls interact directly with prehistoric ecosystems, camping on a Cretaceous beach, gazing up at giant Jurassic sauropods like Diplodocus, and even sampling the local cuisine by eating ammonites.

The setting is a research-focused academic environment where time machines have made paleontology an active, hands-on discipline rather than a purely theoretical one. Alongside the two leads, their colleagues Hannah and Kuriyama round out the main cast, and their daily lives at the laboratory are intertwined with the usual complexities of adolescent relationships. The narrative arc is structured as a sequential journey through geological time, with each period presenting new environments and undiscovered species to document. This journey is grounded in scientific accuracy, as the story is developed under the supervision of professional paleontologist Kentaro Izumi, whose published research serves as the foundation for the prehistoric encounters.