Juan Carlos Thorry is a police inspector who must solve the mystery of the death of the warden of a boarding school for young women, for which he goes undercover as a music teacher. The main suspect is the mischievous schoolgirl María Duval. A series of entanglements leads the protagonists to becoming romantically involved and to finding the culprit.
| Actor | Role |
|---|---|
 María DuvalOlga Arévalo | Olga Arévalo |
 Juan Carlos ThorryInspector Mario Robledo | Inspector Mario Robledo |
 Milagros de la VegaDirectora | Directora |
 Homero CárpenaMorales | Morales |
 María SantosVicedirectora | Vicedirectora |
 Alberto ContrerasGerardo | Gerardo |
 Bertha MossCeladora Graciela | Celadora Graciela |
 Enrique García SaturSr. Arévalo | Sr. Arévalo |
| BBlanca del PradoProfesora de Historia | Profesora de Historia |
| MMary ParetsBeba | Beba |
 Max CitelliDamián | Damián |
| CCarlos FioritiVarela | Varela |
 Cayetano BiondoMédico | Médico |
 Jorge VilloldoComisario Quintana | Comisario Quintana |
 María Aurelia BisuttiNot listed | Not listed |
| AAlfredo AlariaNot listed | Not listed |
 Beba BidartBailarina | Bailarina |
 Patricia CastellNot listed | Not listed |
 Graciela LecubeAlumna | Alumna |
 Norma GiménezAlumna | Alumna |
| DDiana MontesAlumna | Alumna |
| MMarga LandovaAlumna | Alumna |
 Susana CamposEstudiante | Estudiante |