Emiko Hagiwara

When the sky turns red, the moon turns black, and monsters begin roaming the streets, Satsuki Kakeru is at a loss for what to do. Along with his best friend Yuka, they try to decipher why they have been sent to this strange world, which is seemingly empty aside from themselves. However, when the "Red Night" ends, Kakeru and Yuka believe it was all a dream—until it happens again, and they are left in a dangerous situation. They meet four others in the same predicament: Kusakabe Misuzu, an expert swordswoman; Tachibana Kukuri, a strange mute girl who looks uncannily like Kakeru's deceased sister; Hirohara Yukiko, a lively young girl whose personality reverts to that of a cold killer when her glasses are removed; and Tajima Takahisa, a young pyrokineticist. As the six of them band together to survive and discover what this mysterious world is, things take a turn for the worse as six shadows appear before them... [Written by MAL Rewrite]

Two teenagers take in a mutant girl who has lost her memories.

Haneda Takashi has a secret he cannot speak of. To leave his dull school-life, he was supposed to have escaped to another world. However, he is reeled in by certain ties on his heart. One of these is Kobato, his awkward younger sister. The other is Watarai Asuka, his negligent girlfriend. Chitose Shuusuke is a poor freeloader. He passes his days working at various part-time jobs. One day, he has a disastrous first encounter with Tamaizumi Hiyoko. The next time they meet, Shuusuke discovers that they are fellow employees at his part-time job. Narita Hayato sees himself as a "hard-boiled" person. Back-breaking jobs are nothing to him. Hayato shuns normal human contact, but, during the nights, he would get together with delinquents and other denizens of the night. One such night, he meets the cheerful and oblivious Otori Naru. The relationships with these girls will greatly affect these 3 young men. But what, exactly, is the relationship these young men have with each other? (Source: AnimeNFO)