One day, Gordon has a big job for Thomas and Percy; he instructs them to deliver ten cows to McColl Farm. Thomas and Percy are keen for the off, but Gordon reminds them to pay attention and keep track of every cow. Thomas and Percy are having too much fun to listen and set off excitedly for the farm.

Because he isn't paying attention, Thomas has to brake suddenly at a stop sign which bumps the gate on the back of the truck open. Two cows jump out of the wagon, but Thomas doesn't realize until they reach the farm. Only eight cows get out of the truck, but Thomas and Percy have a fun time trying to find the two missing animals.

But when they get back to the farm, they discover even more cows are missing. The engines pretend they are playing hide and seek with the cows which makes spotting them much easier and more fun. They return the missing cows back to their field, but even more cows have gone missing now and they realize that the gate locking the field is broken.

Sandy arrives to fix the gate while Thomas and Percy hunt the missing cows. This time, they sing and make mooing noises to lure the cows back. They count the cows back into the field and all ten are present and correct. Percy is pleased they paid attention, but Thomas reminds him that playing games helped them pay attention.