"Fight or Flight" -- Supergirl's powers are tested when Reactron, one of Superman's formidable enemies, arrives in National City and targets the young hero, on SUPERGIRL, Monday, Nov. 9 (8:00-9:00 PM, ET/PT) on the CBS Television Network. Pictured: Melissa Benoist Photo: Cliff Lipson/CBS ©2015 CBS Broadcasting, Inc. All Rights Reserved