Once upon a time, an unidentified enemy, the Unknown, suddenly appeared. The "Super Evolutionary Railway Development Agency," had developed the "Shinkalion," a robot that transforms into a bullet train, as a countermeasure against this threat.

Early Reins features six beautiful women on a train en route to Sunshine Hill in the early 1800s. When the train is highjacked by robbers and the soldiers on board are caught unawares, another surprise is in store: these lovely ladies can fight! The heroine emerges as Margarette, a young woman determined to become a sheriff although she is somewhat lacking in experience. She gains plenty on this trip, however, and the ragtag team of Western warriors joins forces with another passenger, Spencer, to fight some nefarious bandits and guide the train to safety.

On a moonlit night, Akira Masaki finds herself in a magical world where wizards and humans coexist. Every year, they must face an enormous, deadly moon that attacks the planet. Their only hope lies with the Wizards of the Sage, appointed to fight the supernatural threat. But Akira soon discovers she wasn't summoned by chance—she was chosen to lead them in battle.

Coworkers Yui Mitsuya and Masugu Tateishi are the last people anyone would expect to get along—especially with their constant office quarrels. However, looks can be deceiving: they are actually dating! Afraid to lose the peace of their professional lives, Yui and Masugu play up their discord even more to ensure nobody discovers their secret. As awkward situations and close calls pile up, the risk of Yui and Masugu's coworkers catching on increases. Keeping up the pretense is not easy, but with each new day, their relationship only grows stronger.