After studying law and journalism he began work at the Pueblo newspaper, and at Radio Madrid, on the program Cabalgata Fin de Semana.

He, along with fellow-foreign correspondent Jesus Hermida in New York, was part of a new wave of young journalists who offered a more modern style of reporting, slightly pushing the restrictive boundaries imposed by the Franco regime on freedom of expression.

As a result of his investigatory work for this show, Plaza suffered serious injuries when he was intentionally hit by a car in a failed attempt to silence him.

The following year he started the program, 625 Lineas, which he directed, and hosted with Paca Gabaldon and, later, with Mayra Gomez Kemp.

Two years later, Plaza added a new dimension to the program and hired Tony Saez, a young Canadian of Spanish descent, to coordinate interviews with actors in American television shows airing on RTVE.

Among those who appeared during this phase of the program's history were stars from Michael Landon's NBC series, Little House on the Prairie, Melissa Sue Anderson (Mary Ingalls) and Katherine MacGregor (Harriet Oleson).