If you are referring to a different series, here are other possibilities for a Season 2, Episode 7 titled around "Missing" or "Desaparecido": "Elite" 84 horas desaparecido (TV Episode 2019) - IMDb
This episode is a major turning point that connects the flash-forward investigation of Samuel's disappearance with the events leading up to it. [S2E7] 84 horas desaparecido
Lu (Lucrecia) discovers Cayetana’s secret—that her mother is a cleaning lady at the school and Cayetana's wealthy lifestyle is a lie. If you are referring to a different series,
At a charity fundraiser, a vengeful Lu publicly exposes Cayetana's deception. She also reveals that Samuel and Carla have been sleeping together and leaks a private video of Nadia and Guzmán. She also reveals that Samuel and Carla have
Guzmán begins to suspect Polo might have killed Marina, but Ander—burdened by the secret—lies to him to protect Polo.