Linka is sick, and the planeteers teach her how to safely use antibiotics.

The Planeteers are studying simple organisms and their behavior. They watch as a simple organism keeps splitting into two and eventually has hundreds of identical copies.

Beakman explains that shoes stink because of the bacteria on your feet. He uses a microscope to quickly show that there are bacteria everywhere and then a short animated clip to show how your feet produce oil and sweat that the bacteria eat. This creates smelly biproducts to make your feet stink. He then does a DIY bacteria growth experiment where he grows bacteria from his sweaty feet in a jar of gelatin.

Hank explains innate immune systems and how the signs that we may associate with sickness are actually be symptoms of your immune system working.

A parent grapples with her son's unrelenting fever and talks to the doctors about the possible diagnosis. After finding out that the Strep result was inaccurate, the doctors determine that the patient has Kawasaki disease and put him on the treatment.