The Slender Thread (1965)

Mark Christopher is a 35-year old, award-winning comedy scriptwriter who is struggling to be taken seriously as a drama writer. On Christmas Eve, two police officers bring 17-year old Susan (picked up for vagrancy and brawling) to Mark's apartment. If she spends a few days with him, Mark could use Susan as inspiration to write a script about juvenile-delinquents and Susan could avoid spending Christmas behind bars.