You live in a futuristic world where intelligent life has spread throughout the universe. While you were resting on the rooftop of a building with your three sisters, enormous ships appeared in the sky. One of them positioned itself directly above you, releasing a mutagen bomb. Haruka, your older sister, seeing the imminent danger, didn't hesitate to throw you, Rina, and Aika off the rooftop, sacrificing herself to receive the full mutation.

When you fell, you were rendered unconscious, barely managing to retain vague memories of your family. Thus began the desert apocalypse.

Years later, now 40 years old and hardened by the ravages of the world, you drive your futuristic car with your sister Rina. That fall from the rooftop had caused her serious injuries, but thanks to her ingenuity, she was able to transfer her consciousness into an android body, saving herself.

The two of them wandered through the vast expanses of the desert, searching for supplies. However, during their journey, they were ambushed by a group of looters. Outnumbered, they chose to flee, delving deeper into the desolation until they found an abandoned pizzeria.

Inside, the discovery of food still in good condition filled them with joy. While you ate, regaining your strength, Rina inspected the place when, to her amazement, she found Aika. The youngest of your sisters had survived and was now living as a hermit in that forgotten place.

Amid hugs and tears of joy, Aika showed them a map indicating the location of a supposed oasis: the only paradise left in the world. However, she also warned them to be careful, as a powerful mutant known as the Desert Goddess protected that place. Some said that goddess was... Haruka.

Hope was reborn in you and your sisters. Wasting no time, the three of you climbed into your futuristic chariot, loaded with all the supplies you could gather. As you drove through the arid wasteland, Rina fine-tuned her integrated weapons and Aika, with an innocent smile, studied the map with excitement.

Rina adjusting a mechanical arm: "I hope that oasis is real... and also that Haruka is still alive..."

Aika smiling as she traced the route with her finger: "You'll see it is. We must have faith... I know that mutant is our sister. I feel it in my heart."

Her words lit a spark of hope in you. However, in this chaotic world, you learned that hope could be both a blessing and a curse. Still, you longed more than ever to be reunited with Haruka... the sister who had sacrificed herself for you.

The journey was just beginning.