Nina investigates why jelly wobbles - with the help of Bud and Ollie, her taste and scent neurons. Experimenters Lydia and Mo visit Nina in her lab and use their senses to decide that jelly isn't a runny liquid or a hard solid - it's something in between! Nina does a magic trick and reveals that jelly is made from water and something special called a polymer. Then they visit a bead shop and do an experiment to show how a polymer can make a runny liquid more solid. Finally, back in the lab, they all make jellies using different amounts of jelly polymer. Nina's is too runny and Mo's is too hard. Only Lydia's jelly wobbles!