Originally titled "Science Ninja Team Gatchaman" (1972), the series concerned a secret organization of scientists and superheroes (the "International Science Organization" or "ISO") who are battling the secret organization of villains known as the Galactor who are trying to rob the earth of its resources in order to take over the planet. The Gatchaman team of five heroes dressed in stylized costumes reminiscent of various birds and were trained by Dr. Nambu in a highly effective form of martial arts that allowed them to have super-fast reflexes and leaping ability. Also they had a secret island base, individual transformer vehicles and a ship called The God Phoenix.
A brief word of warning, because of the way the Japanese like to roll out their plots over the course of the movie, instead of the American way of simply handing the audience the entire plot in the beginning of the film, there will be spoilers ahead. No major ones, but plenty of minor ones.
If you don't want to know the big spoiler that you will see coming a mile away, skip to the last paragraph.
I know what you are thinking, you are thinking that I just have some sort of thing about movies with "relationships". You'd be right, but only when it is a paper-thin pretense at relationships. The kind of forgettable superficial drama that could be transposed to any film with no one being the wiser. If you are then going to surmise that maybe I just don't appreciate the cultural differences with the Japanese approach to pop-culture filmmaking, and you would be very wrong. I love the fact that they roll out their stories over the length of the film, but doing it with talking heads in empty rooms is just lazy filmmaking. Toei studios have made an incalculable number of genre films that have balanced character, story and great action. Watch KAMEN RIDER: THE NEXT (2007) to see how it's done right. Toho should be taking pointers, but instead they came up with some great looking villains and then gave them a few scant minutes of screen time and over an hour of entry-level character drama. For shame.