"The Secret of the empty envelope", Shpex T.

The mysterious house on Howard-End Street prefer to bypass. And no accident! Once in this mansion the family of famous archaeologists lived, and one night, while their son Alexander Mercurius was asleep... they disappeared. There are rumors that Alexander still lives in that house under the care of the old butler Einar Stein. After Alex’s parents disappeared, Einar even forbade him to go to school! But once a mysterious letter came to Alexander. True, by mistake, it got into the mailbox to Rebecca and Joe, who moved to Howard-end very, not. But only when Alex finally received an envelope, there was just a blank sheet of paper in it! Rebecca and Joe are sure that this is not an accident. The investigation leads the guys to the labyrinth system near London. Only too late do they understand that someone has long been following them...