"Shinshi Doumei Cross" is a manga series set in a fictional European-inspired aristocratic society, blending elements of romance, drama, and mystery. The story revolves around the protagonist, Arina, a young woman who disguises herself as a man to infiltrate the prestigious all-male student council of an elite academy. Her goal is to uncover the truth behind her father's mysterious death, which she believes is connected to the council's secretive activities.

The student council, known as the "Cross Alliance," is composed of five influential young men, each representing a powerful family within the aristocracy. These members include the enigmatic leader, Kyou, whose calm demeanor hides a sharp intellect; the flirtatious and carefree Aoi; the stoic and disciplined Ranmaru; the gentle and artistic Subaru; and the mischievous yet perceptive Kaname. Together, they wield significant influence over the academy and its students, maintaining an air of secrecy and exclusivity.

As Arina navigates her dual identity, she becomes entangled in the complex dynamics of the Cross Alliance. Her interactions with the council members reveal their individual struggles, hidden agendas, and the societal pressures they face. The narrative explores themes of loyalty, betrayal, and the clash between personal desires and familial expectations. Arina's investigation into her father's death uncovers a web of political intrigue, forbidden relationships, and long-buried secrets that threaten to destabilize the fragile balance of power within the academy and beyond.

The series delves into the emotional and psychological challenges faced by its characters, particularly Arina, as she balances her quest for justice with her growing feelings for the members of the Cross Alliance. The tension between her true identity and her assumed role creates moments of suspense and drama, while the evolving relationships between the characters add depth to the narrative. "Shinshi Doumei Cross" combines a compelling mystery with a richly developed cast, offering a nuanced portrayal of love, ambition, and the consequences of deception in a rigidly hierarchical society.