The new Mayoress, accompanied by her nephew Denzil, is touring Chuggington. She's observing the chuggers working, in order to help her decide who should be the recipient of the prestigious Chugger of the Year award. Koko is sure she's in with a chance - but rather than doing her jobs, she spends her time trying to impress the Mayoress. In the process, she ends up nearly ruining the ceremony. Speedy comes to her rescue time after time. In the end, Koko realises that she hasn't kept her mind on the job and she doesn't really deserve such an honour - but she's thrilled when the Mayoress, with a little help from Denzil, decides that Speedy is this year's winner!