The Mystery in the Rocky Mountains (Real Kids Real Places Series)

When Christina, Grant and their two friends join their mystery-writing Mimi (and Papa!) on a trip to the Mile-High City of Denver, Colorado, they soon find themselves:
Sleeping in a mysterious, haunted palace of a hotel!
Deciphering mountains of clues to solve a mystery!
Reading tattered old books to help solve the clues!
Traveling through tricky tunnels to get to a scary ski slope!
Meeting an amazing woman who once sailed on the Titanic!
But can the kids have fun, stay warm and solve ...