Zepheera would never understand how one could simply drain an entire planet of color, but according to the Doctor it was an extremely malicious procedure. Once every single thing was dulled to black and white, total corrosion of the planet would begin.
When the Time Lord and his four and a half inch tall companion arrived, they were one of the few things left in the area that were not black and white. However, it didn’t take long for them and even the TARDIS were monochromatic. It was a race against the clock to find the machine instigating the calamitous procedure and shut it down so they could even begin to reverse it.
Zepheera clung to the Doctor’s shoulder as he ran through the alien spaceship, nearing the motherboard that could shut down the entire thing and restore the planet to its original state. Desperately, he fished out his sonic screwdriver and gave it a quick buzz, relieved to find it glowing blue. The last color in the world.