In Episode 1 of "Natsu ga Owaru made: Natsu no Owari The Animation," viewers are introduced to Yui Tachibana, a young woman entangled in a complex relationship. Despite having a boyfriend, Yui becomes involved with her teacher, leading to a series of intimate encounters. The episode delves into themes of infidelity and desire, showcasing Yui's internal conflict between her affection for her boyfriend and her growing attraction to her teacher. As the story unfolds, Yui's actions become increasingly bold, reflecting her struggle with her own desires and the consequences of her choices.