Sarasa Ichinokura, a weary adult plagued by chronic fatigue, discovers her lack of energy is linked to a scarcity of 'mana.' Transported to a fantasy realm after a chance encounter with a mysterious deity, she finds herself inhabiting the body of a young girl amidst fantastical creatures. Taken under the wing of a seasoned monster hunter named Nelly, Sarasa craves independence despite newfound vitality. Determined to navigate this unfamiliar and perilous world, she sets her sights on mastering the art of magic, embracing her reincarnation journey with patience and resolve.