How do you get the 69th moon medal in sonic unleashed Wii I've got every single S rank got all the medals in missions and I got over 150 items and still didn't get a secret mission?

I did the same but you relize that there are loads of medal doors that you probably havent explored yet at the Gaia Gates. Your guaranted to find a secret mission in the newly unlocked gates but also check that you havent missed out any items in the previous ones.You just have to find the ones that you couldn't find lat time. Hope it helped :D