Brewster, Maggie and the twins are trying to fly kites but there is no wind. They wonder ‘Where does the wind come from?’ Brewster takes them high up in an air balloon and Sunny Sun explains that warm air goes up and the cool air rushes in to replace it and that’s the wind.

Carrick is building a hot air balloon and asks ‘How do hot air balloons stay up in the sky?’ The friends meet Muldoon the hot air balloon who tells them that the hot air in his balloon makes the balloon rise into the sky and keeps them there.

Mosquitoes are biting Maggie when Helvetica Frog asks ‘Why do mosquitoes bite people?’ Brewster shrinks them down to mosquito size and they meet Bubba Buzzer who explains that it’s only female mosquitoes that bite because they need to feed their babies.

The friends play with Brewster’s new telescope. They use it to look at the moon, but Carrick can only see half, which makes them wonder ‘Where is the other half of the moon?’ They travel to the moon and discover where the other half could be.

Brewster is frightened when he hears thunder, and the friends ask, ‘What makes the sound of thunder?’ Up in the clouds, they meet Cloudy Nimbus who informs them that the clouds rub together and release their shock called lightening and that makes the loud sound.

Brandon shows Brewster and Maggie his composter. They wonder ‘Why do flies like to hang around stinky stuff?’ Inside the composter they meet Mortimer Fly and his mother Mummy Fly, who explain that stinky places are ideal areas to lay eggs.

Brewster, Maggie and Hamish wonder ‘Where does the sky end?’ Brewster takes them to outer space where they meet Zippy Meteor who can help. They imagine all sorts of scenarios that could explain where the sky ends before Zippy tells them their answer.

Brewster and the gang meet Cod Wriggles and ask ‘why is the ocean salty?’ They take a dive into the ocean and use their imaginations to come up with different scenarios before Cod explains that rivers and streams carry salt into the sea from the land.

Brewster and Maggie are at Ginger’s play but she can’t focus because her tummy rumbles. She wonders why and she, Maggie and Brewster visit Bob O’ Tummy. Bob explains when the tummy is expecting food it rumbles in preparation for a meal.

Helvetica Frog is teaching Brewster and Maggie a new dance. She notices a rainbow and asks ‘why aren’t raindrops different colours?’ They meet Drippy who shows them that when the sun shines through the raindrops they make the rainbow colours.

Brewster, Maggie, Ethan and Connor, are playing with paper airplanes. Ethan wonders ‘How do real planes stay up in the sky?’ The friends meet Speedy the Plane who describes how he goes very fast and this means his wings lift him into the air.

Brewster, Maggie and Hamish are making onion soup and Hamish’s eyes water. He wonders ‘Why do onions make our eyes water?’ The friends meet Soup Dragon who explains the onion juice sprays into the air, wafts upwards and make our eyes water.

Brewster, Maggie and Ginger Squirrel see the sunset on the beach. Ginger wonders, ‘Where does the sun go after dark?’ Brewster and Maggie would like to know too, so they ask Sunny Sun who explains that sometimes he goes to the other side of the world.

Brewster and Maggie are at Ginger’s Shadow Show. She wonders ‘What are shadows made of?’ Brewster takes them to meet Atom Adam who explains to the friends that shadows are made when something blocks the light from shining.

Helvetica notices that both the sun and moon are in the sky at the same time and she asks, ‘Why do we sometimes see the moon when the sun is out?’ The curious friends head into space where they meet Sonny Sun and Mr Moon who explain the reason to them.

Brewster and Maggie visit Brandon Badger. Autumn leaves keep falling in his garden and he wonders, ‘Why do trees get rid of their leaves in autumn?’ They meet a little Acorn who tells them that the leaves fall off to help the tree survive in winter.

Brewster, Maggie, and the twins wonder ‘Why do our heads hurt after we drink cold stuff too fast?’ They meet Thinky Brain. He explains that ice makes the mouth cold and when the brain tries to warm things up fast it gives you a headache feeling.

When Helvetica Frog gets the hiccups she wonders ‘What causes hiccups?’ The friends are transported to a human body where they meet Bob O’ Tummy who explains that hiccups are caused by the diaphragm muscle jumping.

Brewster, Maggie and the twins find a toy dinosaur. They wonder ‘Why don’t we see real dinosaurs?’ Brewster takes them to meet Dino-Biggles who describes how long ago the weather changed and the dinosaurs couldn’t survive in it, so became extinct.

Brewster slips on a globe and Hamish wonders “Why does the world look flat?’ The friends become astronauts and talk to the moon. He tells them that because they are so small compared to the earth that it looks flat to them.

Carrick is drinking his favourite juice. The friends wonder ‘what do fish like to drink?’ They jump into the ocean and imagine a Fish Juice Bar and think up a variety of yummy fish drinks. They find the answer with the help of their new fish friend.

Brewster and Maggie help Hamish with his wagon. It is very hot and Hamish wonders ‘How does the sun make it warm?’ Up in space the three friends meet Sunny Sun who clarifies that sometimes he’s closer to the earth and that makes it hot.

Brewster, Maggie and Carrick are bird watching. They wonder ‘Why do we have two eyes but only see one thing?’ Brewster takes the gang to meet the eyes, Arnie and Arlene who explain that with both eyes you can tell how far away things are.

While watching bats return home, Hamish notices the cave is very dark and asks ‘How do bats see in the dark?’ Brewster takes the gang into the cave where they meet Finbar Bat. He shows them how he uses his ears to listen to echoes and move around.