Laughing on the Outside...

Summary
After the Sket Dan help Chūma clean his lab, Bossun accidentally drinks Chūma's drug when he thought it was cola. Chūma explains that he has been researching human emotions and expressions and tells Bossun to be more careful. Then, Hime yells at Chūma for inventing these nasty drug. Despite being mad, Bossun yells at Chūma for leaving his drug in a cola bottle with a big smile on his face. As a result, Bossun's facial expressions and emotions are mismatched. In order to concoct an antidote, Chūma asks Switch and Hime to figure out which emotion goes with which facial expression.

Afterwards, Switch and Hime gather what they had observed. Bossun is angry and makes a happy expression, Bossun is surprised and makes a bored expression, and finally, Bossun is serious and makes an embarrassed expression. When Switch has created a diagram, Hime notices Bossun gave kudos to Switch with a weird expression. She asks Bossun to smile only to make Bossun angry. Switch informs Hime that they cannot force people to laugh. Moments later, Hime and Switch do a little skit that causes Bossun to cry when he is actually bored. Then, Hime resorts to tickle Switch who makes a strange face. Bossun makes a strange face, and his expressions change to a surprised face. He explains that he is worried that his face will get stuck this way for the rest of his life. After a few adjustments to the diagram, Switch has noted that three new findings and reveal a new method to confirm Bossun's emotions, signs with emotions written on them.

With Hime's sad story and the Sket Dance's compliments, they nail down Bossun's sad and embarrassed emotions. Switch and Hime send their findings to Chūma. Chūma whips a concoction to fix Bossun up. After Hime tests Bossun out, they all cheer until they notice the new drug has made Bossun's angry expressions freeze on him.