In the not-too-distant future, the Earth finds itself constantly under attack from extraterrestrial threats. To combat them, the Terrestrial Defense Force establishes the Ultra Garrison, a team of six elite members who utilize high-tech vehicles and weaponry. Joining their fight is the mysterious Dan Moroboshi who is secretly an alien from the Land of Light in Nebula M-78 and transforms into his true alien form, Ultraseven in times of crisis.