Yorick Brown, the last man on Earth, has been crossing North America with his monkey Esperluette for almost two years. Yorick and his road companions, Government Agent 355 and bio-engineer Allison Mann, have finally reached the laboratory of the latter, in San Francisco, where she hopes to understand how Yorick and Esperluette survived. After months of nomadism, landing somewhere is a relief and the opportunity for the various individuals to pursue the trio of finally catch up with them. But if Yorick's group can face these new threats, it is the danger that is invisible to them that could sign the death arrest of the last man and therefore of all hope for the future of humanity. The last - alliance against nature - collects episodes 24 to 31 of the popular series created by Brian K. Vaughan and Pia Guerra, and reveals one of the greatest mysteries of this exciting saga.