Kiyosu Saionji, heir to a prominent banking dynasty, occupies a position within Tokyo's affluent elite in the early 1920s. His engagement to Akiko Hashou, a familial arrangement typical among aristocratic circles, underscores his role in upholding vital social and economic alliances. Despite Akiko's resistance, fueled by feminist ideals and a desire for personal choice, Kiyosu holds to a philosophy that elevates duty and familial honor above individual desires, viewing marriage as an obligation rather than a transaction.

His demeanor presents a reserved, duty-bound contrast to other male figures like Takao Itou. Interactions with Sara Uchida, Akiko's maid, reveal a layer of mutual respect and cordiality, subtly diverging from the era's rigid class expectations. This relationship becomes a point of consideration for Akiko, who contemplates redirecting his affections towards Sara to resolve her own romantic situation.

The Great Kantō Earthquake of 1923 acts as a pivotal catalyst for Kiyosu. Surviving the catastrophe, he endures profound personal loss, including the destruction of Akiko's family estate and the broader societal collapse. Navigating a fractured social landscape where traditional class structures momentarily dissolve, this upheaval potentially reshapes his connection with Sara. Their path hints at a shared future amid the ruins—a dynamic framed narratively as "Lonely Together — Maybe Ever After." His story concludes without full resolution, emphasizing adaptation to irrevocable change over definitive personal transformation.