Sir Topham Hatt's railroad engines, Harold the helicopter, and Bertie the bus learn about good manners and hard work.

Naughty Diesel the train engine gets in trouble by misbehaving but then redeems himself in a time of crisis.

Thomas is just in the way as his friends help prepare for a big ocean show at the docks, but when Percy is startled by one of the exhibits and creates havoc, Thomas helps get things back on track.