—¿Estás espiando a papá por fin? —gruñí, medio en broma. —No digas tonterías —ordenó, pero su voz tembló—. Mañana todo cambia. Anda, vete.
First, I need to consider the context. The phrase "bajo la falda de mi prima" translates to "under my cousin's skirt." That image could be symbolic or literal. Since the user included "espionage" in the title, maybe the story is about a cousin wearing a skirt that hides something or someone. A common trope in espionage could be someone hiding a device or being a spy.
Pero ya no podía retroceder. Lucía era más que una estudiante normal: trabajaba en aquel misterioso laboratorio de la universidad, el que mi tío llamaba "un proyecto para seguridad nacional". Y eso no era ropa común. Era una armadura. Una falda, un chaleco y un dispositivo de espionaje que brillaban bajo la oscuridad.
I should start with a setting that sets the mood. Perhaps a small town where everything seems quiet but there's underlying tension. The protagonist is curious and notices something unusual about their cousin. Maybe the cousin works in a place that has secrets, like a government facility.
—¿Qué haces, Lu? —susurré al acercarme, tratando de disimular mi nerviosismo. —No es de tu incumbencia —respondió sin levantar la vista, concentrada en ajustar un objeto metálico que colgaba de su cintura.
—Si no te vas, juro que llamaré a papá —amenazó, esta vez más seria. —No hasta que me digas qué demonios es ello —sostuve, señalando el objeto.
Start with a setting in a quiet town. Introduce the cousin as trustworthy but with a secret. The protagonist is curious and notices something strange. Maybe the cousin is preparing for a mission. The protagonist finds a device and is involved. Conflict arises, resolution. Make sure the story is for a younger audience, since espionage stories can be intense. Keep it lighthearted with a positive message about trust and discretion.