Under the influence of Irene and her father, Kokoro decides to leave her detective position to pursue a career as an idol in a unique spin-off of the Tantei Opera Milky Holmes series. However, the glitz and glamour of the idol world soon lose their luster for Kokoro, leading her to yearn for her former life solving mysteries. In a heartfelt gesture, Henriette orchestrates a fake theft to show Sherlock the void left by Kokoro's absence, ultimately encouraging her to reclaim her role in the police force.