This text analyzes the disruptive power of teenage characters within long-running serial narratives. The works examined in the corpus of study share a common trait: they feature child actors who have during the course of the shooting(s), grown and turned into teenagers. The first issue is one of generic definition. An analysis of viewers comments posted on the websites of the drama series and soaps under study revealed that the presence of secondary plots devoted to teenage characters (often the children of the main characters) was very mostly perceived as an unwelcome digression, diverting the plot from its thematic center, offsetting the fictional universe. Teenage characters are likely to draw the series, in whole or in part, to its natural generic environment: the teen series. Considered from a diachronic point of view, the puberty process turning children actors into teenagers marks a sometimes conflicting encounter between two temporalities: the one constructed by the narratives, and the one imposed by the unpredictable mutations of puberty.