But CBS is taking a page from “Young Sheldon” with its latest spinoff “NCIS: Origins.” Or as audiences will be tempted to call it, “Young Gibbs.” Harmon (who is an executive producer here) makes a brief return on screen to set the stage for a TV series that functions as one long flashback to 1991 when Gibbs joined the Naval Investigation Service (NIS as it was known back then) fresh out of the Marines and shortly after the murder of his wife and child.