It explained the biological processes that take place in a human cell at the microscopic scale. Specifically, the show followed the journey of an adenovirus as it tries to propagate & infect the body by taking over our cells.
I love science, anatomy, & biology- especially what is going on at the level below the threshold of our senses. The idea that there are all these organized processes and synchronous activity going on trilions of times at the cellular level, throughout any individual's body, is too much to wrap one's head around.
To me, being able to visualize these scenarios is key to understanding them. That is where modern methods of computer animation become so important. Being able to accurately render these microscopic phenomenon using 3D graphics allows us to appreciate the wondrous reality of our own bodies at such a small scale.
It reminded me of another video I've posted that similarly showed the workings of our cellular biology: