Robotech II: The Sentinels was an attempt by Harmony Gold USA to continue the original 1985 Robotech television series. Only three episodes were ultimately animated before the project was canceled in 1986, and a feature-length film was released from footage taken from the completed episodes. The aborted 65-episode Sentinels series would have followed the ongoing adventures of Rick Hunter and Lisa Hayes and the rest of the Robotech Expeditionary Force (REF) during the events of The Robotech Masters and The New Generation series.

Robotech is an American 85-episode adaptation of three unrelated Japanese anime television series made between 1982 and 1984 in Japan; the adaptation was aired in 1985. Within the combined and edited story, Robotechnology refers to the scientific advances discovered in an alien starship that crashed on a South Pacific island. With this technology, Earth developed giant robotic machines or mecha to fight three successive extraterrestrial invasions.