Who Do You Think You Are (8pm, NBC) - Season 3 of this genealogical reality show kicks off with Martin Sheen delving into his family's history. Sheen travels to Ireland and Spain, and discovers his uncle was also devoted to political activism and that another relative had been allegedly imprisoned in Spain.

Seizing Justice: The Greensboro 4 (8pm, Smithsonian Channel) - A repeat of the Smithsonian Channel documentary examing the sit-ins at the Greensboro Woolworth's lunch counter in 1960. More info here.

Supernatural (9pm, CW) - Sam and Dean investigate when bodies branded with a mysterious symbol turn up with their feet and hands severed.

Grimm (9pm, NBC) - Nick finds a black market that supplies the creature world with human organs. Also, he and Juliette befriend a pair of homeless siblings whose friends have vanished.

Blue Bloods (10pm, CBS) -  Danny and his family get caught in a crossfire after Danny's car hits a man fleeing from a gunman and Danny returns fire. Meanwhile, Frank deals with the impending loss of a friend he worked with at Ground Zero.