Nancy Drew and the Hidden Staircase

Based on the popular book by Carolyn Keene, this mystery finds amateur sleuth Nancy Drew (Bonita Granville) determined to rope her boyfriend, Ted (Frankie Thomas), into helping her investigate the strange occurrences that elderly sisters Rosemary (Louise Carter) and Floretta Turnbull (Vera Lewis) have been experiencing in their Victorian-era house. When the Turnbulls are accused of murder, Nancy must act quickly to save the sisters from jail and discover who's been breaking into their home.