A holodeck detective story turns dangerous when the safeties fail.
Captain Picard enjoys a holodeck program in which he plays Dixon Hill, a hard-boiled private detective in the 1940s. Just as the Enterprise is about to meet a delicate diplomatic mission from the Jarada, the holodeck malfunctions, trapping Picard and several crew members inside the story, with the safety protocols cut off and the characters seemingly alive.
The episode is a fan favorite and won a Peabody Award, one of the first honors for the series. It is the first story to explore the dangers and possibilities of the holodeck in depth, and it ends with a thoughtful question about what it means for a created character to be real. Dixon Hill returns in later episodes, and the program remains a Picard hobby.