Rotte, who had been an apprentice pharmacist in a remote town, unexpectedly discovers that she is actually a princess of the Kingdom of Sironia. She is welcomed into the royal palace, but life in the unfamiliar court feels stifling. While secretly entering the Dragon Knights’ order under a false identity, she ends up becoming the Dragon Knights’ dedicated pharmacist due to their shortage of personnel.

Even while hiding her true identity, Rotte finds herself drawn to the earnest yet clumsy commander of the knights, Reginald. Amidst all this, Rotte and Reginald become embroiled in a conspiracy within the royal palace――.