The story is centered around Filena, a princess who was raised as a boy after her kingdom was conquered.

Today, the world is in turmoil due to an unprecedented catastrophe. Suzushirou, a young man who lives as a newspaper scholarship student in Tokyo, had a secret that no one could tell. An incident that happened in the summer of my third year of high school made it possible for me to stop the time around me regardless of my will. One day, Suzushiro meets a person who can share the secret for the first time. Like myself, Nazuna is a girl who has been hurt in her heart and has been able to stop her time. Suzushiro finds out that she is being used for crimes by her brother Seri, and reaches out impulsively. Let's run away with me! Can they move the time they have stopped again? (Source: Eien no 831 official site)

On a world far removed from the Earth, there is a certain kingdom that's brimming with smiles. Fate thrusts young Princess Yuki, filled with idealism, joy, and innocence, into a station in life for which her most endearing qualities are ill-matched. Her kingdom faces grave danger as the Empire threatens the realm's security. Meanwhile, on the opposite side of the conflict, an imperial soldier known as Stella Shining hides behind a facade. However, a time may come where her mask cracks, potentially costing her everything. Princess Yuki and Stella's paths will cross, and the fate of nations will follow. (Source: Sentai Filmworks)

In a story set years in the past, Himura Yuu is a studious and diligent young man intent solely on maintaining his top academic position at Otowa Academy. One day, he meets a mysterious girl named Amamiya Yuuko, who, to his surprise, recognizes him. Memories of a distant childhood, memories rather left forgotten... meeting Yuuko again will force Yuu to confront the regrets and sorrows of their collective pasts and presents. In the present, Kuze Shuuichi may seem like a womanizer, but upon closer inspection, is a man who would rather be left alone. Hayama Mizuki, however, is not the type of girl who would let him be, especially after hearing the beautiful sounds of his violin performance. As Mizuki attempts to become closer to him, Kuze attempts to push her away—the tale of their budding relationship is darkened with undertones of an imminent tragedy.