Harvey imagines himself and his friends in a magical steampunk world, but things come crashing down when Harvey is blamed for breaking a floating city.
Harvey and his friends continue their quest to fix the floating city, but danger looms around every steamy corner.
Back in the present, Irving and Moff about to do various things together, until Irving must care of his baby daughter. Moff becomes upset, then he have to watch Harvey, much to his dismay.
However, Moff is annoyed by Harvey, until he became angered that Fee and Foo arrive. Moff becomes frustrated and explains Harvey that he and his father were best friends, but thanks to Harvey, his friendship is gone. Harvey have a mental breakdown about this as Moff kicks them out.
Harvey's mental breakdown continues as he becomes knocked out by Steamgate that was seen in the last episode.
As Harvey succumbs, he has a dream of being in a floating steaming city. Harvey sings a song of how he likes steampunk. Moff, who's a mayor in his dream, sings a song how he likes being a mayor and his city, they then start floating, due to the crystal, and Irving, who's an engineer in this dream.
Suddenly, the Steamburg is falling due to not having one steampunk left. Harvey fixes with one as everyone claim Harvey as a hero for saving their city. Irving, impressed by child's creative nature by liking the steampunks, decides to make him as his apprentice as he leaves along with Harvey, leading mayor Moff to get upset.
While everything's perfect, Steamburg fell to the ground. Moff says that the crystal is destroyed, due to Harvey's steampunks that is supposed to fix it, it ruined everything. Mayor Moff and everyone, save for Irving, blame Harvey for ruining their chance to float out of city. Moff decides that it's one punishment for destroying the crystal, they banish him out of the city, by throwing him off.
Once Harvey's banished, he falls to the Reject Town, where he was greeted by steampunk rabbit, named Dade. He and everyone (children) sing a song of their town, Harvey thinks that they can live in one city named Steamburg.
Harvey decides to go with Dade to Randl, they explain that the crystal can be in cave crystal in mount of chaos and craziness. However, one way to get in there is to get a airship. He knows, it belongs to the twins, Fee, strict and no-nonsense pilot and Foo, steampunk robot. They ask the airship, for friendship.
After convinced that the friendship could do anything, the twins take Harvey and Dade to the airship to get the crystal cave.
Unbeknownst to them, their plan and conversation is overheard by Les Squirrels. With the conversation between heroes ended, the french thieves decides to call it to their boss.
Moff gets a call from Les Squirrels, he is the one who are boss to them and is furious to learn that Harvey is up to something and goes to call his Freddbots (the parodies of Officer Fredd).
Harvey says that there's nothing they could be stopped, but Moff says he'll stop him, he laughs maniacally as the first part ends.
Following the previous part, Harvey, along with her friends continue their heroic quest to get the crystal. As they journey around the skies, Harvey, Fee and Foo (except Dade) sing a song about being best friends. Back in Steamburg, Moff and Irving sing about it too. The friends have finished, just as they arrive in the mount.
- Miriam Beaks (cameo)
- Doctor Roberts
- Hanzi (cameo)
- The Inspiration (cameo)
- Pooker (cameo)
- Les Squirrels (cameo)
- Randl (cameo)
- Meryl (cameo)
- Bouncer (cameo)
- Officer Fredd (cameo)
- Easy (cameo)
- Ira Fingerman (cameo)
- Michelle Beaks (cameo as an egg)
- "Steamburg" (Harvey Beaks, et. al.)
- "The Mayor of Steamburg" (Moff)
- "Reject Town" (Dade/Claire/Kratz, et. al.)
- "I Can Tell We're Gonna Be Best Friends" (Harvey/Fee/Foo/Moff)
- "Friendship Can Do Anything" (All)
- This is the first hour-long special of the series.
- Members of the crew (such as Ego Plum) referred to this as "essentially the Harvey Beaks Movie", to the point where they brought in a smaller "Big Bang" orchestra to record the songs:
- "The “Steampunks” special was essentially the Harvey Beaks Movie. I treated that music no differently than I would have treated a feature film score. We wanted a big, big sound; we also wanted some traditional old Hollywood-style orchestration. So we had to fill Studio X in Seattle with tons of brass, woodwinds, and strings. It’s my favorite thing I’ve gotten to do on Harvey Beaks."
- The intro to this special is the same as the season 1 intro with a few changes, including the addition of gears to the characters.
- Michelle is still not born in this special but only appeared as a cameo appearance as an egg in the beginning of Part 1 and near the end of Part 2.
- The reason for these changes are due to this episode originally being set to air before "The New Bugaboo".
- And also, in Part 1, Miriam was holding the unborn Michelle and saying "Doctor!" , This might be a sneak peek at the first Season 2 episode where Michelle hatches.
- The tavern scene is a reference to the Cantina scene in Star Wars: A New Hope, with Fee in a Han Solo-esque role.
- Harvey makes a reference to the song "Never Gonna Give You Up" in the same scene.
- Moff saying, "Fly, my Fredd Bots! Fly!" is a reference to the Wicked Witch's line, "Fly, my prettys! Fly!" from The Wizard of Oz.
- The plot itself is reference to AstroBoy 2009 movie as both of the protagonists live in a flying city and later on both fell in a junkyard.
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