In this action-packed Final Season, Captains Strand and Vega, along with the 126 crew, face a deadly train derailment. Judd resigns to care for his disabled son, forcing Owen to choose a new lieutenant between Marjan and Paul. Tommy’s love life hits unexpected obstacles, while T.K. gets a surprise visitor on his 30th birthday that could change his and Carlos’ lives. As newlyweds, T.K. and Carlos face a tough test when Carlos becomes obsessed with solving his father’s murder.