Nagai Atsushi grapples with complex romantic entanglements and personal identity as the central protagonist. He harbors longstanding, unreciprocated feelings for his best friend Saitou Toshihisa, leading to emotional turmoil during Saitou's wedding reception. While drinking heavily there, he encounters Honda Kenzou, a guest connected to the bride, resulting in an intimate encounter between them.

The situation intensifies when Saitou's bride abandons him shortly after the wedding, causing Saitou to seek solace from Nagai. This places Nagai in conflict, torn between his lingering attachment to Saitou and his burgeoning relationship with Honda. Nagai explicitly denies identifying as gay, framing his attractions as specific to individuals.

He develops a romantic and physical relationship with Honda, eventually moving in with him. His ex-girlfriend Ryouko appears briefly, depicted as wanting to resume their relationship for social validation rather than genuine connection. Alcohol frequently precipitates Nagai's physical intimacy and emotional vulnerability, especially with Honda and Saitou.

His development involves navigating jealousy, confusion, and evolving feelings within this love triangle, gradually acknowledging his romantic involvement with Honda while reconciling his complicated history with Saitou.