The sci-fi series calls it a wrap with a series finale fittingly titled "The Last War," as Clarke (Eliza Taylor) and her friends arrive at their final decisive battle after almost incalculable fighting and loss. What remains to be seen, however, is a big question: Does humanity really deserve something greater? Lindsey Morgan, Bob Morley, Marie Avgeropoulos, Richard Harmon, Shannon Kook, JR Bourne, Shelby Flannery and Chuku Modu also are featured.