Yuuhi Amamiya leads a dull existence as a college student until his routine is disrupted by the arrival of Sir Noi Crezant, a talking lizard who identifies himself as a knight of justice. Sir Crezant shares startling news that the world is threatened by the mage Animus, who desires to destroy it with a massive weapon called the Biscuit Hammer. Yuuhi is appointed the Lizard Knight and must work with other Beast Knights to protect the princess and save the planet. Despite his doubts about the danger and his reluctance to put his life on the line, Yuuhi continues with his daily life. But everything changes when he faces a golem produced by Animus. Yuuhi is outmatched, but Princess Samidare Asahina, his neighbor, comes to his rescue. Yuuhi learns that Samidare desires to destroy the world herself, opposing Sir Crezant's mission to save it. Intrigued by Samidare's unwavering goal, Yuuhi strives to become stronger and aid her in accomplishing it. As the duo confronts more golems sent by Animus, Yuuhi finds himself becoming more invested in life. However, the trauma of his past may hinder his progress.