US prime time television drama of the earlier broadcast era featured self-contained storylines and (mostly) amnesiac protagonists. This changed with the arrival of what television scholar Horace Newcomb termed cumulative narrative: Prime-time series of a new era adopted narrative features more typical for daytime soap opera, and leading characters began to remember where they came from. This study explores the organisational patterns and generic implications leading to the rise of cumulative storytelling. It also points to further venues of analysis for backstory narratives and diegetic memory in general.