To end Mystery Time after only a matter of minutes or hours, read through the following steps : Make sure you have another character enrolled as well as your main one. DO NOT let the new character progress as far as gaining access to the Mystery Key. When you activate Mystery Time with your main character and are finished with whatever it is that you are doing, quit your game legitimately (Save and return to the title screen) and load up the secondary character. End the game from this character again (legitimately) and when you load up your main character you should find that Mystery Time has ended and you can, of course, progress on to solve your Mystery etc immediately instead of having to wait 24 hours! I've used this successfully several times and can attest to the fact that so far I have had no negative side effects while exploiting this glitch. This will also mean that you so not need to Time Travel with your DS clock/calender too!