With Charles (Michael Landon) out of town on a job and her siblings elsewhere occupied, little Carrie Ingalls feels lonely and neglected. Her solution: to create an imaginary lookalike friend named Alyssa, and to embark on a series of thrilling adventures. In this special 90-minute episode, the role of Carrie, normally shared by twins Lindsay and Sidney Greenbush, is played by Lindsay alone, while Sidney is portrayed by Sidney -- the first time that both sisters ever appeared together onscreen. ~ Hal Erickson, Rovi