"All species in the world evolve ... except one. Cancer Simplicimus Vulgaris, or the square crab, has suffered with the same evolutionary defect for millennia: it cannot change direction. Condemned to walk in one straight line forever, these crabs living along the Gironde estuary have largely resigned themselves to their fate. However, one seemingly ordinary summer, three crabs decide to take matters into their own claws and rebel against the straight and narrow path they have been sentenced to, upending the entire ecosystem in the process."--Page 4 of cover.