Alex and Whitney are psyched to spend their honeymoon at Alex’s family lake house on “Whitney” (NBC at 8). Unfortunately, they’re greeted by Alex’s father, who is crashing there while working out some marital problems.

The one-hour special “Under Siege: America’s Northern Border” (Discovery at 8) goes inside the Department of Homeland Security and looks at how the agents work as they do everything from patrolling the border to tracking down criminals.

Unfortunately for the Favorites team on “Survivor: Caramoan — Fans vs. Favorites” (CBS at 8), Brandon has what the network calls “a history-making meltdown” and tries to sabotage his own camp.

“American Idol” (Fox at 8) gets down to the Top 10, as the finalists must impress the judges — and voting audience — with a song previously performed by “American Idol” winners.

The Bird-Kersees decide to venture outside the gated community and see a Broadway show in New York City, which inspires Larry to put on his own musical on “The Neighbors” (ABC at 8:30). Unfortunately, his ad­ven­ture in theater risks exposing the family’s true identities.

Robert heads to Illinois to help a mother-daughter team run a cafe on “Restaurant: Impossible” (Food Network at 9), but his mission proves difficult because of their bickering and an inefficient staff.

John has trouble picturing what life will be like after he’s gone from the LAPD on “Southland” (TNT at 10); meanwhile, Sammy is embarrassed when he becomes a celeb after a heroic act, and Lydia meets someone she once sent to death row.

Philip and Elizabeth already have a tough relationship on “The Americans” (FX at 10), given that they are spies pretending to be married, but things get more complicated when Philip meets up with his ex.

“The Tonight Show With Jay Leno” (NBC at 11:35) hosts actor Jerry Seinfeld, entrepreneur Mark Cuban and musical guest Jose James.

Actor Jim Carrey is on “Late Show With David Letterman” (CBS at 11:35), and Richard Tho performs.

“Late Night With Jimmy Fallon” (NBC at 12:35) has actor Steve Carell, actress Abigail Breslin and, for the third day in a row, singer Justin Timberlake.

— Emily Yahr