On the bulletin board in the Tower you can flag this side-quest. You need to look for Crayons in the abandoned school and bring them back.
This is a basic scrounging quest - you need to obtain five (x5) Crayons and then deliver them to Kate.
When you get to the School head inside the area where the Governor was - the Crayons are on the tables and floor in this area - just scan for them and collect them and voila! Mischief managed!
All you need to do after that is RTB and hand off the Crayons to Kate for a job well done!