Before his big show, the Great Bubblini is bursting to know how bubbles form. Bang heads to the laundromat to find out. Josh Gad guest-stars.

When Disco Delilah asks how many tiles she'll need for her dance floor, Beep steps up to learn more about area. Wendi McLendon-Covey guest-stars.

Bo explores why the moon seems to change shape to help Ms. Astronaut Lady safely land her spaceship. Scarlett Johansson guest-stars.

Ms. Firefighter has a burning question about taxes, so Boop visits the Department of Government and Stuff. Gabrielle Union guest-stars.

Beep takes a spin with documentarian Chase Weathers to answer Mr. Cow's question about how tornadoes form. Joe Lo Truglio guest-stars.

Where does glass come from? Mr. Castaway can't make windows for his house until Bo cracks this question. Steve Buscemi guest-stars.

After Ms. Cafeteria Worker Lady's refrigerator stops working, Bing visits the Refrigadome to learn more about cooling. Kristen Bell guest-stars.

Boop travels to the Archive Department to help the all-knowing Socradamus with a fundamental question: What is stuff made of? Simu Liu guest-stars.

When Ms. Clown gets an offer to invest in e-Digital-Clown-Circus-World.com, Bang pays a visit to a TV show about stocks. Julie Bowen guest-stars.

Bo looks into how the internet works after an office worker named Stacy accidentally sends a silly video to his boss. Trevor Noah guest-stars.

Bing races to ask runner Speedy Lightning a question about finding the fastest route for Ms. Pizza Delivery Lady. Jessica Alba guest-stars.