With the collapse of ecosystems and the extinction of species comes the Grief: an unstoppable melancholia that ends in suicide. When Ruby's friend, mourning the loss of the Great Barrier Reef, succumbs to the Grief, the letters she leaves behind reveal the hidden world of the resurrected dead. The Tasmanian tiger, brought back from extinction in an isolated facility, is only the first... but rebirth is not always biological, and it comes with a price. As a scientist, Ruby resists the Grief by focusing her research on resilient jellyfish, but she can't avoid choosing which side she's on. How can she fight against the dead and the forces behind them when doing so risks her home, her life, and the entire biosphere?