Ace detectives Elizabeth and Jonathan Pollack have already solved The Puzzle in the Portrait and The Mystery of the Ancienc Coins. Now, on a summer trip to Germany, they face their biggest case ever. The family stays at a guest house on Observatory Hill, a scientific park with twelve observatories and one lost treasure. A scientific treasure, that is. |
Years ago, the eccentric Professor Vollrath hid his notebooks, filled with valuable observations about astronomy. When asked where he kept them, he would simply draw three dots in the shape of a triangle. After he died in the 1919 Spanish Influenza epidemic, the scientific notebooks were never found. Elizabeth and Jonathan take up the case, with help from their new German friend Peter. As the three sleuths hunt for the long-missing notes, they stumble onto a deeper mystery. Who is sneaking around at night at Professor Vollrath's abandoned observatory? And why does the trail of clues lead to the town?s 700-year-old castle? The answers to these questions lead them to the adventure of their lives!