"Written in Sand"
Season 2, Episode 12
Written In Sand
Air date April 29, 2011
Written by Man of Action
Directed by Chris Graham
Episode guide
"Without a Paddle"
"Night Falls"
Images | Quotes | Transcript

"Written in Sand" is the twelfth episode of season two of Generator Rex and the thirty-third of the overall series. It debuted on April 29, 2011.


While investigating a nanite-free sandstorm, both Rex and Van Kleiss become trapped underground, with their nanites slowly being destroyed. The two enemies must work together in order to survive.


The episode begins with a Providence team, led by Dr. Holiday, entering the desert. The team is investigating a massive sandstorm which is somehow expunging all nanites from the area. Rex is already nearing the middle to try to place a sensor in the sand so that the cause of the phenomenon can be determined. When Rex is ordered to return, he spots Van Kleiss, Biowulf and Skalamander and goes to attack them.

During the fight, Rex and Van Kleiss are sucked underground. At first, things seems to be at a stalemate between them; Van Kleiss keeps creating EVOs using what little animals are left in the area, while Rex simply keeps curing them. Van Kleiss soon discovers that his ability to control EVOs is waning when a scorpion EVO he creates attacks him.

Meanwhile, the research team sent to study the sandstorm is rescued by Agent Six and they soon get to work on locating Rex. Elsewhere, Van Kleiss discovers that not only are nanites being destroyed, but vital elements for survival such as carbon, nitrogen, oxygen and hydrogen are being crushed out of all living things in the area, including them.

Rex states that they need to get out immediately, but Van Kleiss states they need to find the cause of the sandstorm, otherwise it will continue to grow. He begins with deciphering the hieroglyphs covering the walls of the tunnels. Rex pulls Van Kleiss to a higher level, when he starts climbing, also stating that it is no wonder why Rex beats him all the time as they are turning into sand while he is reading "caveman graffiti".

Van Kleiss says that Rex does not have an investigative bone in his body and that he is strong headed, just like his mother. This causes Rex to grow silent and Van Kleiss states that Rex does not like it that he knows more about him than he himself does. Annoyed, Rex says to skip the head games. Feeling they may not get out alive, Van Kleiss decides to tell Rex information about his past, if he asks so.

Rex is not interested in Van Kleiss' deal, saying he already has someone he can trust who can tell him of his past, Caesar. Van Kleiss on the other hand disagrees, saying that Caesar cannot be trusted and according to him, he may not be who Rex thinks he is. Rex asks what is he getting at but Van Kleiss says that if he wants to know more. Convinced to play along for now, Rex decides to play Van Kleiss's game.

He says they will start with something simple: Gabriel Rylander's Omega-1 Nanite and that he knows it is inside of Rex. At the Keep, Six tells White Knight that they have not found Rex yet. White Knight says he will not risk everyone on the ship, even if it is Rex. Dr. Holiday cuts the transmission, simply saying it is the sand. She then communicates with Caesar, informing him that they have not found Rex.

Caesar then reveals that as a byproduct of building his machines, Rex naturally gives off selenium, and that recalibrating the sensors, they might find him. Back in the tunnels, Rex states that his machines are powered by gravity and the only exhaust are atoms of selenium. With the new information, Van Kleiss reveals that Caesar was responsible for the Nanite Project and in turn the Nanite Event.

This revelation causes Rex to damage a pylon, which causes the sand to form into anti-viral sentries designed to eliminate intruders. Van Kleiss and Rex defeat them by working together. It is then revealed that the hieroglyphs are actually circuit boards, as the entire area is part of a massive computer system. Rex takes the direct route to the center of the maze, punching a hole through it.

Once there, they discover the remains of the Salvator Drone and the Providence space station; with this Rex realizes that Zag RS is the main cause of all of this. Van Kleiss then reveals that he knows Zag RS, as it was made as a decontamination program to eliminate nanites that escaped from containment. He then says Caesar was the creator of Zag RS.

While Salvator was damaged beyond repair in the crash, Zag RS was able to survive by connecting to the station's emergency power, and has been using its control over nanites to process the silicon in the desert into new circuitry, and from there elimination of nanites using the sandstorm. In order to destroy Zag RS, Van Kleiss reveals that the Omega-1 Nanite has a self-replicating program and that Rex can make new nanites.

In order to fight the nearly unstoppable force, Van Kleiss and Rex work together against Zag RS, who constructs a crude mech-like body. While Rex provides a distraction, Van Kleiss stabs his gauntlet directly into Zag RS' CPU processor deactivating her. After the sandstorm stops and Zag RS is defeated, Rex notices that Van Kleiss has disappeared.

On the Keep, Caesar explains that he did indeed design Zag RS, but it becoming a "nanite slayer" is very curious. Caesar then reboots Zag RS to figure out how the Nanite Event happened, since Rex asked Caesar if what Van Kleiss said was true. However, Zag RS' memory has been erased. Caesar says that Van Kleiss must have done it, though Rex suspects it was Caesar's doing, heeding Van Kleiss's advice not to trust Caesar.

After Rex says that they only have a lame program with a GPS lady's voice, Caesar is shocked that Rex does not recognize it. Caesar then explains that he designed Zag RS to have the voice of their late mother, Violeta Salazar.


Voice Actor Role(s)
Daryl Sabara Rex Salazar
Wally Kurth Agent Six
Grey DeLisle Rebecca Holiday
Zag RS
John DiMaggio Bobo Haha
J. K. Simmons White Knight
Troy Baker Van Kleiss
Freddy Rodriguez Caesar Salazar

Series continuity

  • Bobo's hatred of sand is shown again, when he is seen shaking sand out of his pants leg, and complaining.


  • This is Zag RS' season two debut.
  • After Rex uses his Blast Caster to try and trip Zag RS, he says that "it worked in the movie". This is likely a reference to Star Wars Episode V: The Empire Strikes Back, as Imperial Walkers are tripped with the use of a cable, much like what Rex was attempting.
  • Zag RS and Doctor Holiday are both voiced by Grey DeLisle.
  • This episode marks the official extermination of Zag RS.
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