Percy Runs Away is the seventeenth episode ever made in Season 1.
After several days of being shut up in the shed, the Fat Controller visits Gordon, James, and Henry. He tells the three that he hopes they have learned they are not as they thought. He informs them that there is a new tank engine named Percy and that Edward and Thomas ran the main line well by themselves. However, he is willing to let them out on the condition that they'll be good and do not complain about shunting anymore. All three agree and they quickly resume their duties.
The Fat Controller then speaks to Thomas, Edward, and Percy and, as a reward for their hard work, allows them to play on the branch line for a few days. Thomas happily collects Annie and Clarabel while Edward and Percy go and play with trucks in the yard. Edward and Thomas leave and Percy is left alone where he enjoys watching the larger engines go by. He also enjoys being cheeky to them.
Later, after doing some more shunting, Percy heads back to the yard, but the points are against him. Percy was so eager to work, he had become careless and forgot that Edward had told him to whistle when he got to the signalbox so that the signalman would know he was there. Suddenly, he sees something that does make him whistle in panic; Gordon, on the same line, heading towards him full speed with the express! Percy is horrified, but cannot do anything and closes his eyes as Gordon gets closer. Luckily, Gordon applies his brakes and stops just in time. However, by now a frightened Percy has begun to move and, intending to run away, begins running backwards.
Percy runs straight through Edward's station and is so frightened he runs straight up Gordon's Hill without stopping. After he decends the hill, Percy quickly becomes tired, but as his crew had jumped out when they saw Gordon, could not stop. Finally, a signalman sees that Percy is in trouble and sets the points into a siding, where Percy lands in a big bank of earth. By now, Percy is so tired he does not care where he stopped.
Gordon arrives and congratulates Percy on starting so quickly and stopping a potential accident. Percy apologises for his previous cheekiness and Gordon pulls Percy out from the bank.
Percy quickly settles into his new role as station pilot. Although he never loses his penchant for cheekiness, he now knows to always be careful when he goes on the main line.
- Henry has the external steampipes of his new shape in the Tidmouth Sheds scenes.