"Romeo x Juliet" is a manga adaptation of William Shakespeare's classic tragedy "Romeo and Juliet," reimagined in a fantastical setting. The story is set in the floating island of Neo Verona, a world where magic and advanced technology coexist. The ruling House of Capulet is overthrown in a violent coup by the tyrannical House of Montague, led by Duke Montague. The Capulet family is massacred, but their infant daughter, Juliet, is secretly rescued and raised in hiding by loyal retainers.

Juliet grows up unaware of her true heritage, living as a commoner under the alias Odin. She becomes a vigilante known as the "Red Whirlwind," fighting against the oppressive rule of the Montagues and aiding the downtrodden citizens of Neo Verona. Her life takes a dramatic turn when she encounters Romeo, the kind-hearted and idealistic son of Duke Montague. Unaware of each other's identities, the two fall deeply in love, setting the stage for a tragic romance intertwined with political intrigue and rebellion.

As Juliet learns of her true lineage and the atrocities committed by the Montagues, she is torn between her love for Romeo and her duty to reclaim her family's legacy. The story explores themes of love, loyalty, and the consequences of vengeance as Juliet becomes the symbol of hope for the oppressed people of Neo Verona. Meanwhile, Romeo struggles with his own moral dilemmas, questioning his father's ruthless methods and seeking a path to peace.

The narrative builds toward a climactic confrontation as Juliet's rebellion gains momentum, and the truth about their families' intertwined fates comes to light. The manga retains the core elements of Shakespeare's tragedy, including the inevitability of fate and the destructive power of hatred, while introducing new twists and fantastical elements unique to its setting. The characters grapple with their roles in a world where love and duty are often at odds, leading to a poignant and dramatic conclusion that echoes the timeless themes of the original play.