When the People from the Future arrived, it was like a world party. They announced themselves, and were honest, and brought all the kinds of technology we needed to survive--infinite clean energy sources, chemistry to repair the climate, and social models we could easily adapt to alleviate poverty and power inequities. All the governments and people of the world embraced them.

But they also brought germs. Germs nobody on Earth had any resistance to.

How could they have missed that?