People prefer to avoid the mysterious house on Howards End. And not by chance! Once upon a time, a family of famous archaeologists lived in this mansion, and one night, while their son Alexander Mercurius was sleeping, they... disappeared. Rumor has it that Alexander still lives in that house under the tutelage of the old butler Einar Stein. After Alex's parents disappeared, Einar even forbade him to go to school! But one day a mysterious letter arrived in Alexander’s name. However, by mistake it ended up in the mailbox of Rebecca and Joe, who had recently moved to Howards End. But when Alex finally received the envelope, it only contained a blank sheet of paper! Rebecca and Joe are confident that this is not an accident. The investigation leads the guys to a labyrinth system under London. Only too late do they realize that someone has been watching them for a long time...