Her older sister is a daughter who wants to be tempted. 14 Sonoda Mion

The movie revolves around the complex relationships between Tatsuya, his girlfriend, and her older sister, Mion. The story explores themes of temptation, desire, and boundaries as Tatsuya finds himself drawn to Mion despite being in a relationship with her younger sister. The title 'Her older sister is a daughter who wants to be tempted' suggests a focus on Mion's character and her desires, which drives the plot forward.