Lassie - Episode 116 - "Transition" - Season 4, #13 (12/01/1957)

This important episode marks the turning point for the Lassie series - the transition from Jeff to Timmy. The death of Gramps (both in real life and on screen) is the catalyst for the Millers leaving the farm, and the new owners, the Martins, taking over. Timmy is given Lassie by Jeff who is going away to high school in the city as he doesn't think she would like living in the city, and thus Timmy now becomes the owner of the collie. In turn, Timmy is also "given" to the Martins to adopt. NOTE: It was interesting to see in the 'going away" scene that Lassie - when given the choice to stay with Timmy or go with Jeff - had chosen to go to Jeff, but he stops her and takes her over to Timmy. This was the final appearance for all the supporting cast of the first 3 seasons, including Tommy Rettig. Both Donald Keeler (Porky) and Jan Clayton (Ellen) would have their closing appearance in the following episode. The closing credits still show Jeff and Lassie walking in the field with the sheep, but this, too, would change in the following episodes.