"Last Quarter" is a supernatural romance manga that intertwines themes of love, fate, and the afterlife. The narrative centers around Mizuki, a high school girl who moves into a mysterious old mansion after her parents' divorce. The mansion, known as the "Last Quarter," is shrouded in eerie legends and is said to be a place where the living and the dead can meet during the last quarter of the moon. Mizuki soon encounters a ghostly young man named Adam, who resides in the mansion. Adam is bound to the house and unable to leave, his existence tied to unresolved emotions and a tragic past.

As Mizuki and Adam grow closer, their relationship becomes a focal point of the story. Mizuki learns that Adam died under mysterious circumstances and that his spirit remains trapped in the mansion due to his lingering attachment to a lost love. The manga explores their evolving bond, blending moments of tenderness with the tension of Adam's spectral nature and the mansion's haunting atmosphere. Mizuki's determination to uncover the truth about Adam's death and her desire to help him find peace drive much of the plot.

The story also introduces other characters who play significant roles, including Mizuki's classmates and a mysterious woman named Reiko, who has her own connection to the mansion and its history. The interplay between the living and the dead is a recurring motif, with the mansion serving as a liminal space where past and present converge. The narrative delves into themes of memory, loss, and the enduring power of love, as Mizuki and Adam navigate the challenges of their unconventional relationship.

"Last Quarter" balances its supernatural elements with emotional depth, creating a poignant exploration of love that transcends the boundaries of life and death. The manga's pacing and structure emphasize the gradual unraveling of Adam's past and the impact of his unresolved emotions on both himself and Mizuki. The story's resolution ties together the threads of fate and connection, offering a bittersweet conclusion that underscores the transient nature of existence and the enduring impact of human relationships.