Ok I'll explain it for you as this a challenge story. Know that it is a digimon story that is Adventure/Romance and pairing in Davis/Kari.
We all know that Davis and veemon get kidnapped by ken aka the dark emperor and is saved before the dark ring is put onto veemon. This is the twist what if the dark ring was put on veemon and the emperor also made a dark ring that could control people as well...or so he thought and tried to control Davis to help him by being his servant to take over the digital world. What if the dark ring on Davis only worked temporarily and Davis had control and pretended to work for the dark emperor and secretly give information to his team more likely Kari. He does tell them who he is not wanting to ruin his cover. The codename I'll let pick. Kari finds out what Davis is during when she is captured by andromon and ken tells Davis to torture her for information, but Davis frees Kari and tells her to escape and tell her not to tell anyone about him being a double agent. Davis ruins his cover after learning everything he can and to save Kari from MetalGraymon that is being controlled by Ken. After that it changes the cannon of the story to the way you want it. Davis is a little smarter than in the cannon because transfers to ken's school and learns under him to not blow his cover. But goes back to his school after he does blow his cover. Kari after learns what happens to Davis starts worrying about him because he is being controlled by the emperor and start to notice him more for who he is and what she tries to do for her before T.K. comes to her school and starts developing feelings for Davis. Veemon is stronger in this cannon because while undercover trains veemon to help his team more when he blows his cover. That is pretty much the summary of the story. So, do you want to try this story out?
Give me a message if you want to do the challenge. Also, I want a write that know digimon and likes to write so that this story doesn't fall behind on updates.