Last night's NCIS, "Faith," almost pushed the team's investigation into a Marine's death to the back burner, thanks to the terrific family/holiday story lines involving the cast.

Not that the murder plot lacked mystery and intrigue in its own right. Follow this link for a full episode guide, then read our review below and see if you agree with our take:

A surprise visit by his dad (a terrifically-cast Ralph Waite, who looks and acts like Mark Harmon's Gibbs) threw Jethro for a loop. He rarely shows, and was acting strangely.

When Gibbs can't quite put his finger on his father's erratic behavior, he brings in the heavily artillery: Ducky and scotch! The old-timers get drunk and share many laughs.

Ducky's armchair psychoanalysis leads to an interesting conclusion: Elder Gibbs isn't demented or losing his faculties, just going through old-fashioned emotional distress.

Since the taciturn father and son aren't exactly good at communicating, Jethro makes some calls back home and presses his dad, who finally admits why he came to D.C.

Gibbs was perplexed by his father's visit and strange behavior.

He recently killed a robber at the Stillwater General Store in self-defense after he threatened customers. He needed his son's advice on how to deal with death on the job.

Gibbs, in vintage fashion, simply said that it's never easy.

These two may have a strained, complicated, uneasy relationship, but it was great to see them want to try (and succeed at) understanding each other in their own way.

The death of a Marine that the NCIS team worked on last night also contained an interesting father-son subtext, related to the deceased's recent conversion to Islam.

This was seen by his retired Colonel and current Reverend father as an act of rebellion. He paid some fellow Marines to try to harass and shame the Muslim out of him.

Pursuit of those Marines led to Ziva kicking asses and taking names in a West Virginia dive bar, but not to the killer. They merely took the money and acted like bigots.

So who killed Marine Tom Ellis as he knelt in prayer?

What would an NCIS-mas be without Abby's awesome weirdness?

It was his own younger brother, who learned about how badly the dad wanted him to renounce Islam and felt ashamed when it didn't work and the Reverend was humiliated.

Sad as it was, the Reverend clearly saw the light and how wrong he had been not to accept his son. He may not have taken his life, but he set into motion events that did.

For once, we got to see a high-profile show defending those of another faith instead of blaming them for the world's problems. It was a rare, refreshing take on religion.

Meanwhile, Abby enlisted McGee to get a kid to see his Navy mom via super-secret satellite feed to the Indian Ocean, and Tony got the icy head of HR for Secret Santa.

Filler? A little. But these three always make things entertaining. The NCIS cast is so solid, the show always retains a very personal feel for a procedural, military drama.

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.