Grandpa's Stolen Treasure

How could she have disappeared after getting this close?Full of anticipation, Kate O'Connell and her whole family wait at the Grantsburg train depot to meet her grandpa and grandma from Sweden. But when the Blueberry Special arrived and the last passenger stepped from the train, Grandpa and Grandma did not appear and no one knew anything about them. Hoping to find them at their last change of trains, Papa Nordstrom and Ben immediately boarded the train for St. Paul.But a telegram delivered in the middle of the night brings the scary news:WE MISSED GETTING OFF AT RUSH CITY STOPWE ARE IN DULUTH BUT MAMA IS LOST STOPHELP ME FIND HER STOPCOME TO IMMIGRANT ROOM STOPGrandma "lost"?! But as Anders, Erik and Kate rush to catch the next train to Duluth and find Grandpa, they will discover that Grandma is not simply lost someone has stolen her away!WHY WOULD ANYONE TAKE GRANDMA?WHAT HOPE IS THERE OF FINDING HER?