Supergirl (8 p.m., The CW) – In the Season 3 premiere, Kara deals with the loss of Mon-El by focusing her energy on a mysterious new threat.
Valor (9 p.m., The CW) – In this new drama, a top secret military mission goes awry and those who return home are treated as heroes.
Me, Myself and I (9:30 p.m., CBS) – Young Alex gives away his most prized possession to impress his crush.
The Island and the Whales (10 p.m., UNC-TV) – This POV documentary looks at high mercury levels in whales, decimated seabird populations and anti-whaling activists.
The Good Doctor (10 p.m., ABC) – Dr. Browne must learn to communicate with Dr. Murphy as they race to the hospital with a donated organ.