In the near future, planet Earth is permanently altered following the sudden—and tumultuous—arrival of seven unique alien races. In the boom-town of Defiance, the newly-formed civilization of humans and aliens must learn to co-exist peacefully.

Seasons

Season	Episodes	Release date	Rating
Season 1 In the year 2046, it's a new Earth - with new rules. Over thirty years after various alien races arrived on Earth, the landscape is completely altered, terraformed nearly beyond recognition. To the town of Defiance, on what used to be St. Louis, comes the mysterious Nolan and his charge, Irisa.	12	2013-04-15	7
Season 2 As the story of Defiance resumes, the lives of the townspeople are in drastic turmoil. The Earth Republic has assumed control of the town, with far-reaching consequences including a new mayor. Nolan traverses the badlands to find a lost Irisa, Amanda has an unexpected new role in the town as …	13	2014-06-19	7.3
Season 3 Following the events of the season two cliffhanger finale, season three of Defiance opens on the eve of an impending military siege upon the town, which has fallen on hard times following the collapse of its lucrative mines.	13	2015-06-12	8

What's left behind the scenes

In the series, the city of St. Louis is called 'Challenge.' A town by that name actually exists in the state of Missouri, 40 kilometers west of St. Louis. It was once home to the American pioneer and hunter Daniel Boone (1734-1820).
The Syfy channel cancelled the series on October 16, 2015, after three seasons.
In the second episode of the third season, Linda Hamilton's character says the phrase, 'Come with me if you want to live.' This is a famous line from James Cameron's sci-fi action film 'The Terminator' (1984), in which Hamilton starred.