Classroom 223-a Sherlock fanfiction

'Rock-a-bye Rosie, at the island. When the wind blows, the mother will laugh. When the bond breaks, the fathers will fall, And down will come Rosie, mem'rie and all. ' Rosie Watson is helping Sherlock out with retrieving secret government plans for Mycroft-if they fall into the wrong hands it could bring the whole nat...