Set in Tokyo, 1969, a junior high school student's life is changed forever when another world, filled with dangerous creatures, appears over planet earth.

In the year 1969, strange things are happening on Earth: a strange formation known as Brigadoon has appeared in the sky. In addition mysterious alien machines called Monomakia descend from this formation to hunt down Marin Asagi... a normal junior high school girl who had been adopted by an elderly couple. Luckily, Marin discovers a strange blue ampoule in a shrine, which summons an alien protector: a sword-carrying, gun-slinging warrior named Melan Blue. Together, Marin and Melan must save the Earth and find out the purpose of these attacks, and at the same time deal with family crises, prejudice, police brutality, and furthermore come to an understanding in their relationship.—Tenchi

Marin is a typical junior high school girl with a sunny disposition and a loving adoptive family. Her life takes a drastic change when a mysterious mirage is seen in the sky above the entire earth. Killer androids called Monomakia descend to earth from the formation in the sky called Brigadoon and begin to hunt down little Marin. She discovers a blue bottle in a shrine as she seeks escape and from the bottle comes a protector, a sword carrying gun slinging alien called Melan Blue, together they must save the earth and deal with family crisis, school prejudice and the police and come to an understanding of Marins past and Melans unexplained mission, as well as learn to trust each other. Set in 1969 Japan with a colorful cast of friends and enemies.—ANN