Sir Topham Hatt is having a long line of coaches painted for the parade, but he only has three colours: red, blue and yellow. He wants more colours. As Thomas and Percy think for ideas, a workman accidentally knocks over the red and blue paint, combining to make a new colour: purple. Soon the friends are mixing all the paint to learn what other colours they can find.

Percy arrives back at Tidmouth shed covered in mud. He's had a busy day and is so tired he just wants to go to bed. However, Thomas and Emily teach Percy the importance of a bedtime routine to ensure he gets a good night's sleep.

When Percy isn't feeling right, it's up to his best friend Thomas to find out what's wrong by teaching Percy about different emotions.

After Percy comments on Butch, the tow truck being a funny-looking engine, Thomas decides to teach Percy that not all vehicles are steam engines. Percy learns that there are many different types of vehicles on the Island of Sodor, of all shapes and sizes.

Poor Percy gets confused when his loud whistle scares away a bird. He only whistled because the bird was whistling too. Thomas explains that his whistle was loud, but the bird was whistling quietly. Loud and quiet are opposites. Percy still doesn't understand, so Thomas teaches his best friend all about opposites.

Thomas and Percy find their friend Emily upset. She lost her friendship chain and can't find it anywhere, but she recalls passing 20 cargo trucks. Thomas has an idea to help by counting twenty trucks, but Percy has never counted up to 20 before. Not a problem when your best friend can teach you.