Secret Weapon: D-5 is the eighth episode of Robots in Disguise. It first aired in the United States on September 17, 2001 on Fox Kids.




The Predacons mug the absent-minded Dr. Yoshimoto to steal a disk that belongs to Dr. Onishi. His fellow scientist tries to fight off Dark Scream by tossing a fire extinguisher. A fire engine arrives, and the Predacons think it might be Optimus Prime. So Slapper licks the disk up and the three retreat. T-AI and Optimus wonder why the Predacons are so concerned with stealing a regular disk. Prowl and Side Burn are contacted to be placed on alert. Side Burn, on the other hand, is more interested in going on a date with a "cute red convertible". Under the sea, the Predacons look at what's on the disk: Images of a steam engine train branded "D-5". Knowing only that the train holds some importance to the doctor, Megatron orders his goons to capture it. In the same room, Dr. Onishi mumbles something about Grampa. Coincidentally, Koji happens to be attending a demonstration running of the D-5 train ("Grampa") with Dr. Yoshimoto. Midnight Express and the Autobot brothers also attend, waiting for the Predacons to attack. The train pulls into the station where Koji and the rest of the crowd of observers are waiting. They board the locomotive and start to enjoy their trip on the anachronism. The rest of Team Bullet Train arrive to make sure the train is protected as much as possible. Meanwhile, X-Brawn, Prowl, & Side Burn are patrolling the countryside, Kelly whizzes by & Side Burn flirts with her. Attempting to escape, Kelly speeds up, but only winds up flying into a haystack after almost hitting a cow. Sky-Byte begins the Predacons' attack on the D-5 train, attempting to invade the train's interior by sneaking down the train's smokestack, but he's quickly knocked off course by a face full of smoke. Dark Scream tries to grab onto the top of the train, but receives a face full of smoke when the train goes into a tunnel. Not entirely giving up his fight, Dark Scream gets up, but is literally railroaded by Rapid Run. Slapper gives his shot at invading the antique, but Midnight Express notices the reptile attacking Grampa and evicts the interloper. The two battle on a beach, and the Autobot clearly has the upper hand. The dastardly Gas Skunk waits ahead with a weapon, and when the train passes, he traps the two remaining train-bots in a pulse field that disturbed their fuses, but D-5, having no fuses, passes through. The D-5 train pulls into the station successfully, and the human passengers disembark. While Optimus compliments everyone, Side Burn complains that he has to miss out on his date. But as soon as they're off, the Predacons commandeer the vessel. The bullet trains chase after the hijacked machine, but Sky-Byte diverts the train away from its protectors. T-AI determines that the train's new track will lead it into the water, but Midnight Express refuses to let Grampa fall into the ocean. The train derails, and Midnight Express jumps into the water after it. Underwater, Megatron tries to grab the falling choo-choo, but Midnight Express snatches the train before it literally falls into the enemy's waiting hands. Afterwards, Koji and the Autobots understand how the endurance of the relic is a symbol of hope.


In the episode


English dub changes


(Numbers indicate order of appearance.)

Autobots Predacons Humans Others


  • Doctor Yoshimoto (4)
  • Doctor Yoshimoto's associate (5)
  • Doctor Onishi (12)


Written by: Marc Handler

Notable quotes


Kelly being licked by a cow.

"They seem to be afraid of this fire engine. Must be some new kind of phobia. I'll look it up in my psycho guide book."

Doctor Yoshimoto analyzes the Predacons.

"This is a police operation. Your dates are not relevant."
"They're relevant to me, bro! You shoulda seen that classy chassis!"

Prowl and Side Burn sum up their personality clash.

"That smoke's a menace! It's clogging up my air filters! (coughs)"
"He's blowing his stack because you made him mad. Steam engines are very sensitive."

Rapid Run and Midnight Express discuss "Grampa".

"I know what this is about. I've fallen under some ancient vehicle curse, right?"

Kelly bemoans the running joke that is her life.

"You messin' with me, pal?! What are you thinking?!"
"I was thinking toads have big mouths and small brains."

Slapper gets burned by Midnight Express.

"Someone's in the kitchen with DAAARRRKK SCCREEAAAMM."

Dark Scream raises the question of who'd want to be in the kitchen with him...

Miscellaneous trivia

  • T-AI says the floppy disk is standard capacity, 1.44 Megabytes. But the correct size is 1.40 Megabytes, since the disks hold 1440 KB of data, but a Megabyte is actually 1024 KB (or (2^10) KB), not 1000 KB.
  • Numerous characters from both factions--most notably Midnight Express--go through this episode either suspecting or flat-out insisting that the steam locomotive is actually alive and sentient. Yeah. And oddly enough, it showed signs of sentience in the end.
  • And speaking of which, the Predacons actually get beaten by the locomotive. No wonder Megatron went looking for better help.








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