In the first installment of the Deborah ga Rival series, Asayo embarks on her university journey, experiencing solo living for the first time. Her neighbor, the attractive blonde individual, surprises her by revealing himself as an 'okama'—Umenosuke Ichimatsu, from the renowned tea ceremony lineage, known by the moniker 'Deborah.' Despite his outward appearance, Deborah harbors a female identity. Asayo, intrigued, befriends him under the guise of a girlfriend, leading to unexpected feelings blooming within her heart.