In the summer of 1913, 17-year-old Patti Robinson (Jane Powell) joins her mother Katherine (Ann Harding), her father Horatio (Louis Calhern), her younger sister Melba (Debbie Reynolds) and her younger brothers McCormick (Gary Gray) and Ricky (Tommy Rettig) on her family's annual vacation at a mountain resort in Kissamee, New York. Though Patti believes that she has reached adulthood and is ready to begin dating boys, her somewhat prudish and over-protective mother believes otherwise and insists that Patti wait until she reaches the age of 18. As soon as Patti arrives at the resort, Billy Finlay (Carleton Carpenter), the 16-year-old son of the hotel manager, resumes his objective from the previous summer and tries to court her. Patti avoids Billy and instead turns her attention to an unfamiliar guest at the resort, a handsome young Cuban man named Demi Armendez (Ricardo Montalban). Falling in love has its follies as Patti soon learns, but it is just a part of growing up.
