|This article is about a/an episode in Mighty Morphin Power Rangers.|
Rita Repulsa seeks to gain Trini's Uncle Howard's invisibility formula to use on her latest monster the Dark Warrior. Meanwhile Billy is tutored by Uncle Howard in martial arts in an effort to improve his skills. In the midst of things, Uncle Howard is captured and ransomed. The monster's price: the Invisibility Formula.
Trini's Uncle Howard creates an invisibility formula in his lab before going to visit his niece. At the Youth Center, Jason trains a class while Billy admires Jason's talent from afar. Bulk and Skull harass Billy and put him in a garbage bin. Trini helps him out and tries to cheer him up with news that Uncle Howard is coming over. Even that fails to make Billy happy. Billy decides to re-enroll into Jason's class.
The girls congratulate Billy on his new lesson with Jason at the Center. Trini talks about Uncle Howard, who Jason recognizes as a great martial artist. Howard finally shows up, but leaves his jar of invisibility formula on Ernie's counter. Howard decides to tutor Billy.
Goldar, Baboo and Squatt go to Howard's lab to find the invisibility formula. Squatt ends up drinking something that isn't the formula and gets sick. They all return to Rita who punishes them for their failure. The Dark Warrior says to send the Putties to capture Howard.
In the woods, Howard is teaching Billy. The Putties kidnap Trini's uncle and tie him up in a cave with explosives. The Dark Warrior demands the formula, but Howard can't remember where he put it. The monster threatens that he'll get it from Trini then.
Billy returns to the Center with a ransom note from the Dark Warrior. Trini doesn't have the formula, but the Rangers go to Zordon for help anyway. Ernie looks in confusion at the strange bottle of green substance on his counter.
Zordon informs the Rangers of the situation and the five teleport to the cave where Howard is. They fight the Putties before saving Howard. After Trini's uncle wanders off, the five morph and confront the Dark Warrior. Rita turns her monster into a giant, but the Megazord destroys him.
At the Youth Center, Jason tests Billy's skills. Billy receives a yellow belt and Howard finds his jar. Trini's uncle drinks his creation and saves Billy from Bulk and Skull's bullying.
- Austin St. John as Jason Lee Scott (Mighty Morphin Red Ranger)
- Thuy Trang as Trini Kwan (Mighty Morphin Yellow Ranger)
- Walter Jones as Zack Taylor (Mighty Morphin Black Ranger)
- Amy Jo Johnson as Kimberly Ann Hart (Mighty Morphin Pink Ranger)
- David Yost as Billy Cranston (Mighty Morphin Blue Ranger)
- Paul Schrier as Farkas "Bulk" Bulkmeier
- Jason Narvy as Eugene "Skull" Skullovitch
- Richard Genelle as Ernie
- ??? as Uncle Howard
- David Fielding as Zordon
- Romy J. Sharf as Alpha 5
- Richard Steven Horvitz as Alpha 5 (voice)
- Machiko Soga as Rita Repulsa
- Barbara Goodson as Rita Repulsa (voice)
- Takashi Sakamoto as Goldar (Zyuranger Footage)
- Danny Wayne Stallcup as Goldar (American Footage)
- Kerrigan Mahan as Goldar (voice) (as Ryan O'Flannigan)
- Takako Iiboshi as Finster
- Robert Axelrod as Finster (voice)
- Minoru Watanabe as Squatt
- Michael J. Sorich as Squatt (voice)
- Hideaki Kusaka as Baboo
- Dave Mallow as Baboo (voice (as Colin Phillips)
- Tom Wyner as Dark Warrior (voice)
- Uncle Howard's lab is clearly Billy's garage lab set.
- Billy was already enrolled in Jason's class, but this error is due to a scene for this episode being cut and put into Day of the Dumpster. Here, he is "re-enrolled" (which Billy says off screen, but really it was dubbed into the episode).
- In the original footage featuring the Dark Warrior and Uncle Howard, it can be seen that the Dark Warrior has blue clothing under his camo armor.
- This is the second scene involving the five teenagers from Day of the Dumpster was actually filmed for this episode.
- In the Viewing Globe, Zordon shows the teens footage of the Dark Warrior's creation, including Finster's machine.
- This episode was originally titled "Ninja! Impossible".
- In the original Japanese episode, Dark Warrior receives a blast from Titanus, but Titanus has yet to be introduced yet.
- Baboo's appearance in original footage shows him wearing a sculpted mask instead of having a human face.
- This episode expresses kids not to drink poisonous bottles without a label.