After winning a free European vacation, the Turtles journey to Paris, France. Meanwhile, Shredder, Rocksteady and Bebop are planning to steal metal from the Eiffel Tower on Bastille Day in order to power up the Technodrome.
Still in Paris, the Turtles and Master Splinter visit the Louvre. Meanwhile, due to Shredder's incompetence, Krang's new Hyper Rocket Thruster becomes a Rust Encruster with which he plans to oxidize the world's most famous landmarks and monuments unless world leaders use their power reserves to bring the Technodrome back to Earth.
In the Austrian Alps, Krang plans to use his new invention to melt the Alpine glaciers, flooding the low-lying villages.
The Turtles take a tour of Venice, Italy, just in time for the annual Mardi Gras festival which April O'Neil is covering for Channel 6. Meanwhile, Shredder and Krang plan to hold the priceless treasures of Venice to ransom by using Krang's HydroFluxor to flood the city.
Two intergalactic art collectors are stealing the priceless artworks from the museums of Florence, Italy. The aliens are taking only artworks designed by the Renaissance masters that the Turtles are named after.
After a fight with Shredder causes Donatello to be struck by a laser beam, his personality changes to become a costumed superhero known as the Dark Turtle. His mission: Seek out and destroy Shredder. Meanwhile, a Triceratops-like alien race called Triceratons invades Earth.
The Turtles and Splinter arrive in Lisbon, Portugal, just in time for the annual Running of the Bulls. Meanwhile, Shredder and the mutants will use Krang's new heat ray magnifier to burn the city to ashes using the power of the Sun unless the Turtles can stop them. * Greg Berg voices Donatello and Bebop in this episode, instead of Barry Gordon.
The Turtles and Splinter journey to Dublin, capital of the Republic of Ireland, land of myth and legend. Meanwhile, Shredder, Rocksteady, and Bebop use Krang's Rainbow TransCharmer to transform all of the cute furry animals in Dublin into vicious beasts.
Shredder takes possession of the mythic sword Excalibur and proclaims himself "King Shredder". The Turtles, along with Merlin, must take it from him or else the Medieval period will merge with the modern world.
The Turtles and Master Splinter travel to Athens, Greece, while April and Irma buy a mysterious amulet from a flea market vendor. Unfortunately, Krang and Shredder have tracked enormous power readings straight to April's necklace, which is slowly transforming her into the Queen of the mythical underwater city of Atlantis.
The Turtles take a trip on the famous Orient Express that runs from Gare de Lyon in Paris, France to Istanbul, Turkey. But Shredder is also on board and is planning to use Krang's new Super Charger to launch the Orient Express into the world's largest oil field.
A small alien being named Quirx crash-lands on Earth, with intergalactic stormtroopers in hot pursuit. The Turtles must figure out how to get Quirx back to his home planet before Earth is destroyed.
In Amsterdam, Netherlands, the Turtles must stop Shredder from stealing the Duchess Diamond, that Krang needs to power his Laser Dimension Blade. Shredder has some competition though, as two bumbling thieves also want the diamond for themselves.