What to Watch on Sunday: ‘Mercy Street’ returns, ‘Librarians’ finale

Mercy Street (8 p.m., UNC-TV) – In the Season 2 opener, the staff unites to save one of their own following Lincoln’s visit.

Also on . . .

N.C. Bookwatch (Noon, UNC-TV) – Art Chansky talks about “Game Changers: Dean Smith, Charlie Scott, and the Era That Transformed a Southern College Town.”

The Librarians (8 p.m., TNT) – In the Season 3 finale, the library is simultaneously infiltrated by DOSA and Apep.

The Young Pope (9 p.m., HBO) – Voiello considers his options, and Sister Mary outlines the pope’s policy toward questions and concerns from the media.

Homeland (9 p.m., Showtime) – Carrie and Reda fight for their client, while Quinn chafes at his new life.

Hunted (10 p.m., CBS) – In this new competition series, nine teams of two try to last 28 days without being captured to win the $250,000 prize.