Scientist Nina and her young experimenters investigate the human body and find out why it is brilliant.
Nina investigates how people stay balanced, with the help of her sense neurons Belle, Felix and Luke. Experimenters Hannah and Megan visit Nina in her lab and discover that ears have a special liquid inside them, which helps people to balance.
Next they go to a circus school. There they learn to walk a tightrope - and feel how muscles all over their bodies help them to balance. Finally, back in the lab, they do a very wobbly experiment to see how the sense of sight also helps with balance.