Thomas and Rosie are shunting when Thomas invents a game that involves splashing engines by racing through puddles. Sir Topham Hatt tells Thomas to have a washdown before collecting himself and Alicia Botti. On the way, Thomas tries his "Splish, Splash, Splosh" game on Charile, who finds the game fun.Thomas accidentally ruins James and Emily's loads. He then splashes through the biggest puddle yet, but only succeeds in putting his fire out and covering Miss Botti and Sir Topham Hatt with muddy water. Rosie rescues Thomas and he offers to finsh James and Emily's jobs so they can go to the concert. At the concert, Rosie wants another game of "Splish, Splash, Splosh", but Thomas decides that he's had enough of that game.