Terra Nova Season 1 Episode 12 (12/19/11)
Terra Nova prepares for Lucas's return through the portal, but they are blindsided by a suicide bomber. Jim gets knocked out for a couple days and wakes up to a Terra Nova taken over by Lucas and his team of military forces.
Taylor, Shannon and the rest fight back, slowly but surely taking out many of Lucas's men. It all culminates with Jim sneaking back through the portal, where he blows up Hope Plaza so that no more bad guys can make their way through.
Lucas's military heads out of Terra Nova, and go north to the Badlands.