In "Tres Marias: Sannin no Sei Shojo" Episode 1, viewers are introduced to Dr. Fuwa, a physician notorious for exploiting his female patients, leaving him with only his nurse, Megumi, to assist him. The narrative takes a provocative turn when Dr. Fuwa is summoned to a remote island to investigate a mysterious illness afflicting the nuns-in-training at a secluded church. Upon arrival, he discovers that the sisters are experiencing unexplained sexual arousal, a condition that contradicts their strict vows of chastity. As Dr. Fuwa delves deeper into the investigation, his methods become increasingly unorthodox, blurring the lines between medical examination and personal indulgence. The episode explores themes of power dynamics, forbidden desires, and ethical boundaries, all set against the backdrop of a secluded religious community. The animation captures the tension and moral ambiguity of the storyline, with detailed character designs and atmospheric settings that enhance the provocative nature of the series.