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!