Work has become hard for the engines on the Island of Sodor. The viaduct on the main line is being repaired, with the arches being strengthened. As the Fat Controller is unwilling to close the railway during repairs, the work is taking a long time and all engines crossing the viaduct must cross slowly and carefully, lest they risk it collapsing under them. Because of this, the engines are often late making it to the junction where Thomas waits for his passengers.
Thomas complains that the engines are just going slowly to make him late; one morning he grumbles at Henry for his lateness. Henry defends himself by telling Thomas that they have to go at a reduced speed during the repair work, but Thomas is uninterested and he leaves to try to make up for lost time.
Normally when Thomas stops at the station, Bertie arrives soon after and his passengers go straight from him to Thomas. However, when the larger engines are late for Thomas, then Thomas is late for Bertie's passengers and now they often find themselves waiting on the platform, causing Bertie to become angry with Thomas. When Thomas arrives that day, Bertie tells Thomas that he thought he could go faster than that. He then remarks they should have another race, thinking he could now beat him causing an exhausted Thomas to become angry and blame the main line engines for "dithering" on the viaduct and claims it to be an excuse for laziness.
Another day, James arrives later than ever. He apologises, a hold-up at the station combined with the delay at the viaduct causing his lateness. Thomas, as usual, has no interest in excuses and leaves grumbling. He attempts to get to the station as fast as he can, but is unable to make up very much time. However, things change when Thomas spots Bertie at the level crossing, where his radiator is steaming. Thomas tells Bertie he is late, but Bertie tells Thomas that he feels dreadful and his driver is unable to repair him. Thomas running so late is a bit of relief, as he can now pick up the passengers here instead of having them be stranded. Thomas no longer feels angry and is sorry for Bertie, and promises to send help at the next station. Thomas leaves and takes the passengers home.
When Bertie is repaired, he and Thomas make up their argument and both agree that sometimes being late can actually be quite useful.