In the not-too-distant future, the Earth finds itself constantly under attack from extraterrestrial threats. 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, secretly an alien from the Land of Light in Nebula M-78, who transforms into his true form in times of crisis, Ultraseven.

Kate runs an old-fashioned café in a seaside town, and develops a strong, if sometimes volatile, friendship with asylum-seeking African doctor Koji. Although from different worlds, Kate and Koji are similar in ways they do not see for themselves.