The Secret of the Black Lady

Dasha and her friends are bored to death. It has been a long time since any investigation. If only some case would come up!
And then it turns out that the teacher Zanyuda's beautiful sister Lydia has gone missing. Not just missing, but with the money from selling the apartment! What happened? And why was Lydia deceiving everyone that she was studying to be a journalist? And what was she doing in the black car?

The kids have so many questions... The case might not be so simple after all!