A Most Singular Engine

A Most Singular Engine is the second episode of the twenty-first season.

Plot
Diesel makes mischief between Daisy and Harvey by telling them both that the other is boasting of being unique. However, the two become friends while assisting each other on a job, and Diesel does not understand why. Read more at https://www.freeview.co.uk/tv-guide/text-only#ZiFBvTEfVvBFbQQg.99

Characters

 * Diesel
 * Daisy
 * Harvey