Two souls are condemned to a cycle of reincarnation, taking the form of various animal species on the brink of extinction. As they live and die as penguins, otters, crows, and other creatures, they confront the meaning of existence under the shadow of total annihilation. A simple, unassuming rock appears throughout their journey, serving as both a grounding presence and a symbolic object whose purpose shifts with each new life.

The story begins in a penguin colony where a nihilistic penguin named Pen decides that life is an inherently painful experience. Seeing death as a form of mercy, he plots to drive his entire species to extinction, leading to shocking violence including a penguin homicide in the opening pages. His companion Marle engages in an equally absurd but more passive act, incubating a stone instead of an egg. After their deaths, the two souls are reborn as Japanese sea otters, then as Hawaiian crows, continuing their journey through different ecosystems and social structures.

The narrative unfolds across six mostly self-contained chapters, each exploring a distinct philosophical theme through the lens of a different endangered species. The otter chapter examines societal pressure to reproduce and abandon personal joy, as an otter who loves juggling is told to stop its childish hobby and start a family for the survival of the species. The crow chapter explores the loss of culture and tradition, showing how meaning passes between generations and what disappears when only a few remain. The final chapter returns to the penguins as a sequel to the opening, bringing the thematic threads full circle.

Throughout these chapters, the two reincarnating souls appear in different relationships to one another, sometimes as parent and child, other times as friends or rivals. The humble rock reappears in each incarnation, sometimes as a substitute egg to keep warm, sometimes as a microphone at a rock concert, occasionally barely mentioned but always present. This recurring object becomes an anchor across lifetimes, a silent witness to each species struggle to find purpose.

The manga grapples with heavy themes including genocide, suicide, and the weight of being among the last of ones kind. It questions whether reproduction is inherently meaningful, whether play and art have value in the face of extinction, and how love can exist when total destruction is inevitable. The tone balances pitch-black comedy with genuine tenderness, contrasting cute animal artwork with profoundly unsettling situations. A penguin attempting to bomb its own colony sits alongside moments of quiet reflection about warming a stone simply because it feels right to do so.

Rather than offering easy answers, the story argues that meaning must be created individually, even when that meaning appears absurd to others. The act of juggling, maintaining traditions, keeping a rock warm, or simply continuing to exist can become its own justification. The transmigratory framework allows the same consciousness to experience multiple strategies for facing annihilation, from violent nihilism to gentle resistance, ultimately suggesting that purpose is not found but made, and that love and protest have power even when they cannot prevent the end.