Just as you had to complete all your required tasks in Wizard City before you were given the key to Krokotopia and just as you had to complete all your required tasks in Krokotopia before you were given the key to Marleybone so must you complete all your required tasks in Marleybone before you will be given the key to MooShu.
You have completed the quest "Fetch Bones!" given to you by Watson Scotland in Yard Roof You need to speak to Clancy Pembroke in the Royal Museum to obtain the quest "Stolen Away"
