The lesson of 'El Lobo' the movie (inc. a spoiler to some)
Fascism is based on a lie, so Fascists can't but betray everyone even when they themselves believe they are acting in honest intentions. The very nature of Fascism is morally perverted and it's impossible for Fascism to create anything good.
That's why El Lobo's one man mission working as a mole for Falangist Police against terrorism and for peaceful political change in Euskadi is doomed from the beginning.