Dungeon Travelers 2: The Royal Library & the Monster Seal is a dungeon crawler role-playing video game and the sequel to To Heart 2: Dungeon Travelers within the To Heart franchise.

Long ago, in a bygone age, this land was contested between gods, humans, and the otherworldly evil known as the Demon God. Under the flag of the holy maiden Vitoria, the humans fought a long-waging war against the Demon God and her pawns, which they dubbed monsters. Things went on apace, as for so long they had, until it came to be the 395th year of the Era of the Gods. It was in this year that the master alchemist Siegdrad invented a technique for capturing monsters into magical tomes called Sealbooks. Those who wielded this power became known as the Libras, and their success against the monsters was nothing short of astounding. Thanks to their efforts, the monster population plummeted, until even the Demon God herself was sealed away. Under the auspices of a new human order, the world began to flourish. So it was that that year came to be declared the first of the King's Era. Vitoria, having united the continent under human rule, assumed her rightful throne as the First Queen of Romulea. ーExcerpt from the Founding History of the Kingdom of Romulea, Chapter 1, Section 10. It is now Year 499 of the King's Era. In the halls of the Royal Library of Romulea, a new story is beginning to unfold...