"NCIS" Season 11, Episode 11, "Homesick" is the CBS crime drama's Christmas special. It is also the first NCIS holiday for probie Ellie Bishop (Emily Wickersham), who has completely taken over Ziva's desk. Presence of adorable children usually makes NCIS specials more endearing, but this one is a little different.

Spoiler alert: This recap contains major spoilers from NCIS Season 11, Episode 11, Homesick. Watch the NCIS 11x11 sneak preview (promo video on YouTube) if you're okay with minor spoilers. Dr Abby Sciuto (Pauley Perrette) sums up the episode with a question on "infectious" things around Christmastime. Meanwhile, Leon Vance (Rocky Carroll) someone related to his deceased wife.

"After a mysterious illness strikes uniformed mens' children, Gibbs and the team investigate the cause. Meanwhile, Abby and Jimmy partner with the Naval Medical Research Center to determine the strain of illness, all in hopes of delivering a cure before the holidays. Also, Vance struggles with forgiveness as his estranged father-in-law makes a surprise visit to his home," says the NCIS 11x11 episode summary on TV.com.

Here is a recap of highlights from NCIS Season 11 Christmas special (NCIS 11x11):

- Ellie Bishop learns Tony DiNozzo (Michael Weatherly) almost died of pneumonic plague. But Caitlin Todd does not get a mention in the recall. (Sasha Alexander's Kate Todd stayed by Tony's side when she thought he was dying.)

- Ellie thinks bio-terrorism might be involved in the mystery illness that plagued dozens of military personnels' kids from different schools. It turns out one of the Christmas Santas unwittingly spread some African-borne virus. Her first Christmas present for Leroy Jethro Gibbs (Mark Harmon) is some cinnamon munchies made by her mom. Gibbs is secretly pleased.

- Leon Vance (Rocky Carroll) introduces his father-in-law to his kids. Their late mom told them he's dead over some painful abandonment history. But Leon realizes it's time to forgive him. (Paula Newsome's Jackie Vance died in an episode from NCIS Season 7)

- Tim McGee (Sean Murray) will have some holiday drinks with DiNozzo. Girlfriend Delilah Fielding (Margo Harshman) is nowhere in sight. (Margo, who is also known in CBS' "The Big Bang Theory" as Sheldon's assistant, Alex Jensen, was last seen in NCIS Season 11, Episode 1.)

- Jimmy Palmer (Brian Dietzen) and wife have found a pregnant woman giving up the baby for adoption. As much as he'd like to celebrate, he thinks it's too early. Solving a mystery illness sending kids to hospital on Christmas becomes a personal case to him.

- Abby Sciuto (Pauley Perrette) and friend Carol (Meredith Eaton) from the Naval Medical Research Center team up to lecture Palmer about optimism, kindness, and forgiveness. Leon gets hit by the holiday message.

- Ellie Bishop mentions "my husband" at least twice throughout the episode, as if making it stick to viewers' mind that she is really married. Spoilers reveal the NCIS agents Gibbs, DiNozzo and McGee will work with the hubby in a future case.

WATCH: NCIS 11x11, 'Homesick' Promo Video (CBS promo on YouTube)

NCIS Season 11, Episode 11, Homesick, is the last NCIS episode for 2013. The crime drama returns to CBS for its winter premiere on Jan. 7. Some fans who wished there'd be a holiday greeting from Ziva David (Cote de Pablo) to Tony DiNozzo were disappointed, but still hoping to see Ziva back even in a guest role.

More NCIS Season 11 Spoilers and TV Guide Features

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