When Worlds Collide Part 1
Teenage Mutant Ninja Turtles (2012 TV series) episode
Fullsizeoutput cf0.jpeg
Season Code: 510
Episode: 109
Original airdate June 18, 2017
Written by Todd Casey & Elliott Casey
Supervising Producer Patrick Krebs
Directed by Sebastian Montes
Voice Direction Andrea Romano
Supervising Director  Ben Jones & Ciro Nieli
Episode chronology
← Previous Next →
"End Times" "When Worlds Collide, Part 2"

Tales of the Teenage Mutant Ninja Turtles Season 5
March 19, 2017 - November 12, 2017
List of Teenage Mutant Ninja Turtles episodes


  1. Scroll of the Demodragon
  2. The Forgotten Swordsman
  3. Heart of Evil
  4. End Times
  5. When Worlds Collide, Part 1
  6. When Worlds Collide, Part 2
  7. Yojimbo
  8. Osoroshi no Tabi
  9. Kagayakei! Kintaro
  10. Lone Rat and Cubs
  11. The Wasteland Warrior
  12. The Impossible Desert
  13. Carmageddon!
  14. The Curse of Savanti Romero
  15. The Crypt of Dracula
  16. The Frankenstein Experiment
  17. Monsters Among Us!
  18. Wanted: Bebop & Rocksteady
  19. The Foot Walks Again!
  20. The Big Blow-Out!

Season 1Season 2 - Season 3 - Season 4 - Season 5

"When Worlds Collide, Part 1" is the fifth episode of the fifth and final season of the 2012 TV series, the one-hundred and ninth episode overall in the series, and is also part 1 of 2 of the When Worlds Collide dual-episode event.

Production-wise, it is the tenth episode of Season 5, the one-hundred and thirteenth episode overall, and is also part 1 of 2 of the mid-season finale of Season 5. It first aired on June 18th, 2017.


Part 1 of 2. The Newtralizer returns to New York City more powerful than ever before and starts to target the Utrom. With the help of Mona Lisa and Sal Commander, the Turtles must fight back to defend their city.


Major characters

Minor Characters


Somewhere in outer space, a Salamandrian fighter force travels through the cosmos, lead by Mona Lisa and her superior, Sal Commander. However, their general R'Kavaka soon comes on a hologram with news that a rogue Salamandrian named 'K'Vathrak' (whom Sal Commander has a grudge against as it was that rogue Salamandrian who cost him his left eye) had been spotted on Earth and is hunting benevolent Utrom. Realizing that planet Earth is where Raphael lives, Mona and Sal Commander break off from the fleet to head to Earth.

In New York City, three Utrom hunt for the rogue, who ambushes them in an alleyway. It is implied that they are killed by the Salamandrian.

Meanwhile, after watching the latest episode of "Space Heroes: The Next Generation," Raphael is ticked off by how each of his brothers has a love interest and he doesn't.

- Raph sees that April and Donnie are too busy having a popcorn fight to watch Space Heroes.

- While walking past the dojo, Raph sees Leo and Karai playfully sparring whilst exchanging some flirtatious banter, during which Leo says to her that she needs to slow down, it's just a spar session. At which Karai states that even though she loves him, she won't go easy on him.

- When walking into Mikey's room, Raph finds the latter talking to Renet, via the means of a futuristic video phone which projects a 3D image of her and Mikey joking that in doing so they've having formed a long-distance relationship.

Raph storms out to his room to vent his anger on his drum set, in addition, to sulk and rant his complaints to Chompy, only to soon get a call over his space helmet, that Fugitoid gave him, from Mona, who reports that she is on her way to Earth with Sal Commander. Raph is ecstatic by this. When Mona and Sal Commander land on a rooftop and meet up with April, the Turtles, and Karai, we see Raphael immediately embrace Mona Lisa. Seeing this, Karai finds it weird that Raph is in love with a newt, but also shows some unsettled discomfort around Leo's comments on Raph having weird tastes, which is basically reminding her that she herself is dating a Turtle. After this, Mona Lisa and Sal Commander explain why they are there, and the Turtles realize the rogue Salamandrian is really the Newtralizer, going after Utroms and traveling back and forth between Earth and Dimension X to heedlessly wreak havoc without mercy.

Meanwhile, at the Utrom High Council, Queen, Pawn, and Rook are concerned about what's happening and ask Bishop to investigate. Bishop agrees to take an Earth Protection Force commando team to deal with the Newtralizer and the recent arrivals of Mona and Sal Commander on Earth as well. Soon enough, Bishop and the EPF commandos attack Sal Commander and Mikey after they split up from Raphael and Mona.

Before going after them, Mona explains to Raphael that she and Sal Commander had to deal with Lord Dregg, who survived his presumed death by the Triceratons, and managed to still launch his invasion of Salamandria. They fought him off, but Dregg swore to return.

After rescuing Mikey and Sal Commander, they are surrounded by Bishop and the EPF commando team. Thankfully, once Raphael and Mikey explain that Mona and Sal Commander are the ones who helped the Utroms previously in Dimension X with the Kraang, Bishop and the EPF release them and agree to aid them against Newtralizer, with Bishop acting as the bait to draw Newtralizer out. Karai and Leonardo team with Donatello and April to investigate and ambush the Newtralizer. Despite their best attempts, Newtralizer proves too powerful, and once Leo and Karai (along with Donnie and April) arrive before Newtralizer can eat Bishop, who has them retreat back to the Utrom High Council chamber, where Rook reveals a device that could help deal with Newtralizer, but he arrives, disables Queen's Miss Campbell body, decapitates Rook, and nearly eats Pawn, before Bishop leads the Turtles and everyone else back to NYC. However, as they fight Newtralizer at a power substation where he fought Leo, Karai, Donnie, and April earlier, where April weakened him with water, he manages to apparently electrocute and disintegrate Mikey. Enraged, Raphael zaps him with Rook's weapon, but before it can destroy him completely, electromagnetic interference saves Newtralizer.

The reason soon presents itself: Newtralizer's old friend and ally, and the one that the Turtles hoped they would never see again: Lord Vringath Dregg, now in a new living command ship, which quickly begins laying Vreen eggs to begin taking over the city. As Newtralizer retreats to the ship, the Turtles, April, Karai, Salamandrians, and Bishop look up in disbelief and shock as things have just gone from bad to worse. The episode concludes with Karai and Leonardo looking up into the sky in horror as Lord Dregg's ship hovers overhead, and Vreen insects start infesting the city.


  • When April uses water to short out Newtralizer's tech, she creates the illusion that she's waterbending, similar to Katara from Avatar: The Last Airbender, who Mae Whitman also provided the voice of.
  • The captions spell Renet's name as Grenette.
  • As of this episode, Casey is the only one who has not been to Dimension X.
  • This episode reveals the following:
    • G'Throkka has a bionic eye because Newtrailzer took out his real one and left him to perish by his wound.
    • Michelangelo has kept in touch with Renet since their last encounter in "Tale of the Yokai".
    • Salamandrian's are forbidden in Earth's galaxy.
    • Lord Dregg survived after being sucked out into space by the Triceratons in the episode "The Ever-Burning Fire".
    • Newtralizer's real name is K’Vathrak.
    • Renet is seen without her helmet on. Yet when she took her helmet off in "The Crypt of Dracula", Michelangelo looks at her as if it was the first time he saw her without it. This was due to the episodes being aired out of production order as this episode was actually meant to be aired after the "Monsters vs. Mutants" saga.