Mary Poppins, the unflappable nanny of the Banks c hildren, is back again! This time she returns to save the house next door to the Bankses'. The house has always been empty, and so has become the treasure of Cherry Tree Lane--each neighbor has filled it with personal dreams. Then a new, but not unknown, tenant arrives, and peace in the lane is gravely threatened. Can Mary Poppins, in her own magical, whimsical way, resolve the crisis?