"Please Save My Earth" is a science fiction manga series that intertwines themes of reincarnation, extraterrestrial life, and human relationships. The narrative begins with a group of seven individuals who discover they share recurring dreams about a distant past. These dreams reveal that they were once scientists stationed on the moon, observing Earth from a research base. The scientists, originally from a distant planet, were tasked with studying Earth's ecosystem but met tragic ends during their mission. In their current lives, the characters are reincarnated as ordinary humans, unaware of their past identities until their memories gradually resurface.

The central protagonist, Rin Kobayashi, is a middle school student who becomes the focal point of the group's awakening. Her counterpart in the past, Mokuren, was a botanist with a deep connection to Earth and a pivotal figure among the scientists. Rin's memories of Mokuren's life, particularly her relationship with the enigmatic Shion, drive much of the emotional core of the story. Shion, in his current incarnation, is a young boy named Shion Takashiro, who struggles with the overwhelming memories of his past self. The dynamic between Rin and Shion becomes increasingly complex as their past and present identities blur, revealing unresolved feelings and conflicts.

Other key characters include Alice Sakaguchi, a strong-willed woman who was once the team's leader, and Issei Kudo, a quiet and introspective boy who harbors deep guilt over his past actions. The group's memories reveal a web of interpersonal relationships, betrayals, and unfulfilled desires that shaped their lives on the moon. As they piece together their shared history, they must confront the consequences of their past decisions and the lingering emotional scars that transcend lifetimes.

The plot delves into the psychological and emotional struggles of the characters as they grapple with their dual identities. The reincarnation aspect is not merely a plot device but a means to explore themes of identity, forgiveness, and the enduring impact of past actions. The story also incorporates elements of mystery and suspense, particularly as the characters uncover the truth behind the destruction of their moon base and the role each of them played in the tragedy.

"Please Save My Earth" balances its science fiction premise with a deeply human narrative, focusing on the characters' emotional journeys and their attempts to reconcile their past and present selves. The series is notable for its intricate character development and its exploration of complex relationships, making it a compelling blend of speculative fiction and introspective drama.