Air date: February 18th, 2019 (UK), December 4th, 2018 (US)
When Sidney can't remember what he's supposed to be doing with the engine parts he is shunting, Paxton assumes the guise of a 'special agent' - keeping him under surveillance and piecing together the clues in order to solve the mystery.
Tropes:
- A Day in the Limelight: For Sidney and Paxton.
- An Aesop: Sometimes, when we have a problem to solve, it helps to do it together with a friend.
- Ascended Extra: Besides Paxton and Sidney being the focus of the episode, this episodes also gives screentime to obscure characters such as Whiff, Reg, and Skarloey.
- Bait-and-Switch:
- As mentioned in Comically Missing the Point below, Sidney says that Paxton solved the mystery, only for Sidney to claim that the parts are for Diesel.
- After they figure out that the parts are actually for Sidney, Sidney laments that he doesn't know how to get to the Dieselworks since he's broken down. Paxton says that this is another mystery, but then just offers to tow Sidney to the Dieselworks.
- Clueless Detective: Sidney, who has no idea that the engine parts were actually for him.
- Comically Missing the Point: When Sidney points out that Diesel bumped him and jangled his parts, and Paxton bumped him and Sidney's buffer fell off, Sidney comes to the conclusion that the parts must be for Diesel.
- Continuity Nod:
- Sidney mentions that Diesel bumped him. This could be a reference to "Springtime for Diesel", since Diesel bumped him in that episode as well.
- In the And Knowing Is Half the Battle segment, Thomas recalls the events of "Timothy and the Rainbow Truck".
- Farts on Fire: At the end of the episode, Sidney emits some fire, which resembled farting to many viewers.
- Foreshadowing: Sidney's faulty horn, broken buffer, broken lamp, and him coughing up black smoke are all foreshadowing to the fact that the engine parts were for Sidney.
- Imagine Spot: Paxton has one where he and Sidney are in a noir-esque setting.
- It Was with You All Along: Sidney goes on a quest to find out who the engine parts are for, only to realize that they were for him.
- Noir Episode: Not completely, but the episode has the mystery plot and jazz music typical of a noir film, and also, Paxton's Imagine Spot is in black-and-white.
- Pun: After some garbage falls on Sidney, he says "That clue was a load of rubbish!".
- Rule of Three: First, Sidney's horn doesn't work. Then, his lamp doesn't work. Finally, his buffer falls off. Paxton pieces together these clues and draws the conclusion that the parts were for Sidney the whole time.
