The Biker Mice return to Mars, but also end up having a run-in with their old enemies the Nomad Rats, who are led by an old friend of the Biker Mice who has gone bad.
This is the final episode of the 2006 series.
This episode contains examples of
- Back for the Finale: Harley returns in the final episode of the 2006 revival when her only appearance in the original series was in the three-part episode "Once Upon a Time on Mars".
- Bittersweet Ending: The Biker Mice finally return to Mars and use the regenerator to re-hydrate their planet, but Harley has betrayed the Martian mice since the last time they met and supposedly gets killed shortly after she comes to her senses.
- Call-Back: The Nomad Rats bear a strong resemblance to 1993 villain Tunnel Rat.
- Evil Costume Switch: Ever since siding with the Nomad Rats, Harley has exchanged her beige coat, green shirt, and green pants for black form-fitting tights and a purple mask.
- Face–Heel Turn: Harley, Vinnie's old girlfriend on Mars and member of the Martian freedom fighters, is revealed to have sided with the Nomad Rats because she was disfigured shortly after Mace kidnapped her and assumed the Biker Mice abandoned her when nobody showed up to help her.
- Grand Finale: This is the final episode of the 2006 revival and also has the Martian mice finally use Stoker's regenerator to end their planet's drought.
- Heartbroken Badass: Vinnie is distraught that his old flame has gone rogue and especially gets sad when she supposedly dies.
- Heel Realization: It eventually hits Harley that using the regenerator to make Olympus Mons erupt is not the way to save the planet.
- Heroic Sacrifice: Harley takes it upon herself to de-activate the regenerator before it goes critical, but ends up supposedly killed when the Biker Mice stabilize the volcanic eruption.
- Musical Episode: A good deal of the episode consists of the characters singing.
- Never Found the Body: While Harley appears to get killed by lava from Olympus Mons, her body is not found. Modo and Charley even attempt to cheer up Vinnie by informing him that Harley may have survived somehow.
- Please Keep Your Hat On: While not directly stated, the flashbacks that appear during Harley's song "Hard to be Harley" reveal that she now wears a purple mask to hide her face after it got scarred during the Plutarkian invasion.
- Redemption Equals Death: Harley eventually comes to her senses and stops the regenerator before it goes critical. Unfortunately, while the Biker Mice are able to stop the lava flow before it destroys the planet, Harley appears to get killed by a stray flow of lava.
- Retcon: The 1993 series ended with Harley getting kidnapped by the Nomad Rats, this episode changes that to Harley being saved by the Nomad Rats.
- Villain Song: There are songs for every antagonist involved in the episode.
- The Nomad Rats sing "We're Nomad Rats" when they first make their presence known to the Biker Mice, Charley, and Carbine.
- Hannibal T. Hairball and Dr. Catorkian sing a duet called "Dig Deep" during their first scene in the episode, where they mention their plan to conquer Earth being foiled as well as their forged alliance with the Nomad Rats and general gloating about how evil they are.
- The renegade Harley has two Villain Songs. The first one is "Hard to be Harley", where she explains what happened to her ever since the Biker Mice lost her and why she betrayed them, while the other one is "Mine, Mine, Mine" and is sung when she gloats about how well her plan will go now that she has Vinnie under her thrall.
