Where was the father of the large family going and why?

As she nears the seminary, Sara spots the children of the large family bidding their father, Mr. Carmichael, farewell: he is going to Moscow to try to find a certain "little girl." Sara wonders who the little girl is, oblivious to the fact that she is the child in question. Meanwhile, the Carmichael children watch her go by, wondering what her story is and why she is always being sent on such seemingly unpleasant errands.