In a nutshell...
ROBOTECH is a sweeping science-fiction anime epic of humans defending their homeworld against alien domination. The saga is told through the eyes of characters caught up in a series of wars that erupts when a mysterious spacecraft crash-lands on Earth at the turn of the millenium. The secrets of alien knowledge aboard this vessel were unlocked, leading to the development of "Robotechnology" and the creation of a vast arsenal of robotic "mecha" to defend the Earth against the alien threats that would eventually strike to lay claim to the mysterious power source known as "protoculture."
ROBOTECH has often been called a "space opera" because it is not just action-packed entertainment, but also an engaging drama.