Twelve-year-old Heidi Smith is looking forward to a fun summer in 1991. She and her family go to their mobile in Lake Nyona near Rochester, Indiana. She ran to the dock where she spotted an eerie blue light coming from the top of the hill on White High Island, a forest across the lake. Local legend tells the tale of Hans Bachmann, a former Nazi and escapee of Compound 1-A at Papago Park, Arizona in 1944, who might be living on the island.
This fact raises her curiosity. She asked her friend, Craig Markey, to row over to the island with her and her ten-year old brother Scott to investigate the situation. However, he doesn't come back to the dock. What happened to him? Did Bachmann kidnap him? Heidi's sleuthing game becomes a deadly mission.