Red River begins when Yuri Suzuki, a Japanese teenager, passes her college entrance exam and shares her first kiss with the childhood friend who has become her boyfriend. Soon she notices that water turns violent whenever she goes near it, and one night hands rise from a puddle in the street, drag her under, and pull her out of modern Japan into an ancient village in the Middle East. Armed troops seize Yuri before she can understand where she is or why she was taken, delivering her to the queen's palace as a human sacrifice. The world awaiting her is the Hittite Empire of the 14th century BCE, where ritual, fear, and political violence shape every part of court life.
Trapped in a land far removed from her own, Yuri must survive the palace that holds her prisoner and uncover the force behind her abduction. Her fate becomes entangled with Prince Kail Mursili, whose struggle against assassins, rival claimants, and royal conspiracies broadens the story into a historical fantasy of war, palace intrigue, and romance. As Yuri learns to navigate a kingdom that seems to have chosen her destiny before she ever arrived, Sora wa Akai Kawa no Hotori follows her through a world of danger and power where returning home is no longer the only future before her.