One morning on the Island of Sodor, Toby takes Henrietta to the Steamworks to have new seats installed. Victor assures her that her new seats will be both comfortable and stylish, but after Kevin crashes, he tells her that they may just be comfortable. Toby asks Henrietta what he's going to do without her, and Henrietta assures him that Sir Topham Hatt will find something to keep him busy.
Toby sadly leaves the Steamworks and makes his way to the sidings near Knapford Station. He sees Thomas, who asks him what's wrong. Toby tells Thomas that Henrietta's at the Steamworks, and he misses her so much. Thomas asks Toby how long Henrietta's been at the Steamworks, and Toby tells him, "About twenty minutes.". Just then, Rosie puffs in with Sir Topham Hatt, who is riding a coach nearly identical to Henrietta. Sir Topham Hatt tells Toby that since Henrietta is away, he found him a new coach named Hannah. Hannah eagerly greets Toby, who nervously greets her back. Hannah tells Toby that she is excited to be working with him, and Sir Topham Hatt is pleased with that. He tells Toby and Hannah that he's sure they'll work splendidly together, but Toby isn't so sure.
As Toby sets off, Hannah is upset with how slow Toby is going, and tells him to go faster. A fast James passes by them, and Hannah is impressed with how fast he can go. Toby tells Hannah that neither he nor her are built for high speeds, and he prefers to go steady and safe. Hannah tells Toby that today might be the day for him to blow away the cobwebs and feel the wind beneath his wheels, but Toby assures her that's happy just the way he is, much to her disappointment.
Toby and Hannah come to a level crossing, where the gates are just about to change to let Bertie pass. Hannah tells Toby that if he goes a little faster, he can get his jobs done quicker. She then dares him to go faster. Toby nervously warns her that the gates are closing, but she tells him that if he speeds up, he can get through them before they close completely. She pushes him, causing him to go faster and past the gates. Bertie honks and asks Toby what he's playing at.
Hannah enjoys going faster as she and Toby reach a red signal, where Percy is about to switch lanes. Hannah tells Toby to go even faster, but Toby warns her that Percy is at the switch. Hannah tells Toby that he can get past him, and Toby shuts his eyes as he passes by Percy, who screeches to a halt. Percy scolds Toby, telling him he's not an express engine, and tells him to slow down. Toby tells Hannah that what they just did was very dangerous, and that they should have stopped to let Percy pass. Hannah continues to ignore Toby, and enjoys going faster.
Toby and Hannah reach Dryaw Station, where the passengers are waiting. Toby screeches to a halt, and Hannah asked him why he stopped. Toby tells her that he stopped so they could pick up their passengers, since it's their job. Hannah doesn't think too kindly of passengers, as she doesn't like having to stop to hang around. The Stationmaster blows the whistle, and Hannah pushes Toby to go fast, also bumping her passengers.
Toby and Hannah come to the top of Gordon's Hill, and Hannah is impressed with how steep it is. She looks forward to going down the other side really fast, but Toby doesn't. As they go down the hill, Toby tells Hannah to put her brakes on. Hannah ignores Toby, telling him, "Who needs brakes?", but Toby tells her that she's his brake coach, and they're going too fast. Hannah bumps Toby, wanting him to go even faster. As they reach the bottom of the hill, Toby puts his brakes on, just barely managing not to fall off the rails.
Toby and Hannah soon reach a siding, and Hannah wants Toby to take her up and down Gordon's Hill again. Toby has had enough of both going fast and working with Hannah, so his driver uncouples him. He leaves to go to the Steamworks, leaving Hannah behind. Hannah begs Toby to come back, telling him he can't leave her behind.
At the Steamworks, Henrietta is still having her new seats installed, and is surprised to see Toby. Toby tells Henrietta that Sir Topham Hatt made him work with a new coach, who made him go too fast, called him a slow coach, and made him go through red signals. Henrietta asks Toby what he did with the other coach, and Toby tells her that he left her on a siding. Henrietta scolds Toby, telling him he shouldn't have done that. She then tells him to go back and collect her or he'll get in trouble with Sir Topham Hatt.
Toby goes back to the siding, realizing that Henrietta is right, and that he shouldn't have left Hannah behind. When he gets to the siding, he is surprised to find that Hannah isn't there. He wonders what happened to her, but he soon finds out that Hannah is now being pulled by James. Toby is surprised, and tries to tell Hannah that she's not built for high speeds. Hannah doesn't listen to Toby, and she enjoys being pulled by James, as she can now go as fast as she wants. She tells James to keep going faster and faster, when suddenly, a bolt flies off her. Hannah soon realizes that she's going too fast, as her wheels are wobbling, and her couplings are rattling. Just then, Hannah's gates open, and she tells James to slow down. James keeps going faster, and Hannah's body begins to break apart. One of her gates flies off her and lands on the rails. Hannah begins to regret wanting to go faster, and tells James to slow down. Her coupling breaks, and she is diverted onto a siding.
Toby catches up with Hannah, and blames himself for leaving Hannah on the siding. Hannah then admits to Toby that the accident was her fault. She now realizes that going fast can be fun, but it can also be very dangerous.
Toby takes Hannah to the Steamworks, where Henrietta's new seats are finally installed. Toby and Henrietta are happy to see each other again, but Henrietta is surprised to see Hannah, who nervously greets her. Toby asks Henrietta how she and Hannah know each other, and Henrietta tells him that Hannah is her sister. She then tells Toby that she used to call Hannah "Hasty Hannah" because of how fast she wanted to go. Victor assures Toby and Henrietta that he, Kevin, and the Workmen will soon have Hannah fixed up and looking better than new. Hannah thanks Victor as Toby leaves her in the Steamworks' care and collects Henrietta.
As Toby and Henrietta leave the Steamworks, Toby tells Henrietta he's glad to have her back, and Henrietta tells Toby she's glad to be working with him again. Toby tells Henrietta that he's sure Hannah has learned her lesson today and that next time, she'll want to go just a little bit slower. Henrietta then tells him, "Not if you know my sister!", implying that Hannah has had to learn that lesson before. Toby chuckles, but then Henrietta starts acting like Hannah by bumping him and telling him to go faster. The two chuckle it off as they leave into the sunset.
This episode provides examples of:
- Aesop Amnesia: After Hannah nearly gets torn to bits at James' wheels, Toby tells Henrietta that he's sure Hannah has learned a lesson about going too fast. Henrietta tells Toby that Hannah has had to learn that lesson before.
- Alliterative Title: Hasty Hannah.
- Be Careful What You Wish For: Hannah loves to race at high speeds, and wishes that she could go as fast as she wants. She gets her wish when Toby leaves her in a siding and James pulls her, but it leads to her falling apart as James goes faster and faster.
- Foolish Sibling, Responsible Sibling: Hannah is the foolish sibling to Henrietta's responsible sibling. Henrietta treats Toby with respect and knows that tramway coaches are not built for high speeds, while Hannah demands the engine pulling her go faster and faster, even if it means going past closing crossing gates and other engines at switches, and leads to her coming apart.
- Foreshadowing: Toby warns Hannah that neither of them are built to go fast. She discovers this the hard way.
- Idiot Houdini: James seemingly suffers no consequences for unknowingly dismantling Hannah.
- Just Train Wrong:
- As Hannah's couplings snap, James continues on the track while she is diverted to a siding.
- Hannah makes Toby speed through a level crossing that was opening for Bertie. Level crossings rarely give way to roads first (since cars can obviously stop easier than locomotives) and thus the gate should have been open for Toby when nearby anyway.
- Lovable Coward: Downplayed here, while Toby is left a Nervous Wreck by Hannah, it is for pretty logical reasons that she continuously shunts him past several near-misses. He does also try to put his foot down with Hannah at first, only bolting after she nearly derails him speeding down Gordon's Hill.
- Nervous Wreck: Poor Toby is left visibly trembling after a run with Hannah shunting him dangerously across the line.
- Rail-Car Separation: Hannah gets pulled by James after Toby leaves her on a siding. Thanks to James, Hannah is now able to go as fast as she wants, but because she didn't listen to Toby's warnings that tramway coaches like her are not built for high speeds, she begins to break apart as James goes faster. Eventually, her coupling breaks and as a result, she is diverted onto a siding as James leaves without her.
- Rule of Three: Hannah puts Toby in danger three times. First, when she pushes him across a level crossing where the gates are about to change to let Bertie pass, then when she pushes him across a rail crossing when Percy is about to cross it, and finally, when she pushes Toby down Gordon's Hill, where Toby just barely manages not to fall off the rails.
- Runaway Train: Less intentional example with Hannah than with the Troublesome Trucks. She becomes so insistent about Toby speeding up that she starts bumping him forward, unintentionally putting him in danger.
- Stealth Hi/Bye: Hannah does this to Toby as she is taken by James.Hannah: Hi, Toby!
Toby: Hannah?
Hannah: Bye, Toby! Wheee! - Uncanny Family Resemblance: Being Henrietta's sister, Hannah resembles Henrietta, but with a yellow-orange color scheme.
