The self-paced event “A Tiny Voice, A Heavy Burden” will begin on 8/21 and end on 8/28. You can find Sherry the Mouse on her pillow in Castle British, and you can start the quest by simply saying “hello”. If you have any trouble, I have written a basic guide to how self-paced events work here: http://legends.uoem.net/investigation-guide/
If you run into any problems or if you get stuck, feel free to email me. Good luck!