Is Tony DiNozzo (Michael Weatherly) thinking about proposing marriage to ATF Special agent Zoe (Marisol Nichols)?

Bishop (Emily Wickersham) tells McGee (Sean Murray) that Tony and Zoe are having problems, but could the problem be that Tony is thinking about popping the question? When Tony comes in, he is in a cheery mood, so there's no indication of any problem there. Then Tony shares that he is going to get the results of a DNA test to find out who his ancestors are. It sounds as if he might be interested in nesting.

Tony teases his co-workers that if he gets the results he hopes for, they will have to call him "Lord Anthony."

At the same time, Bishop is also having relationship issues. Things aren't getting any better between her and Jake (Jamie Bamber), so she plans a trip to St. Johns in the Virgin Islands so she and Jake can rekindle their marriage.

Unlike last week, the "Incognito" episode is mainly about the case. Gibbs gets a phone call from a Maj. Newton, who was involved in an armory-theft case that Gibbs and DiNozzo had worked earlier and considered closed. But Newton was like a dog with a bone and refused to let it go. He always thought there was an accomplice, but when Gibbs and DiNozzo go out to Quantico to meet with Newton, he turns up dead.

At first, it looks as if he fell while jogging, but there isn't enough blood at the scene and Ducky (David McCallum) says he has to find out why. But it is Abby (Pauley Perrette) who discovers the truth. Abby puts the data from Newton's fitness tracker in her computer, which shows that the major's heart stopped beating but his body kept moving! And since this isn't a show about the undead, Newton's death is labeled a murder.

When they examine Newton's quarters, DiNozzo discovers a plastic knife, wrapped in a napkin inside an envelope. Gibbs figures that it is evidence that Newton was going to turn over, but he doesn't know to what it's connected.

A finger print on the knife leads them to Captain Dean Hudson (Bart Johnson) and his wife Lauren (Stephanie Koenig), who deny having seen Newton while he was in D.C.

Gibbs meets with Lauren's lawyer, who tells him that Lauren's marriage to Dean was the only thing her father ever disapproved of that she had done. Even so, he left her his fortune.

When surveillance footage from the commissary on the base shows the Hudsons with Newton, Gibbs sends Bishop and McGee undercover as a married couple -- shades of Ziva (Cote de Pablo) and DiNozzo, who did this and had a grand time in a hotel. But things are rough between Bishop and McGee, because McGee had inadvertently spilled the beans to Jake about the trip to the Virgin Islands, not knowing it was a surprise Bishop planned for their anniversary.

The pair don't learn much undercover, but back at the lab, Abby discovers a discrepancy between the photos on Lauren's North Carolina and Virginia driver's licenses. When she double checks the fingerprints, she realizes that they don't belong to the same woman!

As Gibbs and DiNozzo drive to arrest the Hudsons, Gibbs asks what's up with the sudden interest in his ancestry. DiNozzo replies, "All I have is Senior (Robert Wagner). I've been thinking about family. I don't see kids in my future. I guess I am searching for a sense of belonging." Which means Bishop was right: DiNozzo and Zoe are having problems.

McGee is with Lauren when he learns that she is a fake, but his cover is busted by a Marine, asking him if Newton's murder has been solved. Lauren runs, but doesn't get far and McGee arrests her at gunpoint.

Meanwhile, Bishop decides to break into the Hudsons' home. She tells Abby, "Gibbs is always telling me to take the initiative." She asks Abby to watch the monitors, and she goes across the street, climbs in the bathroom window, and starts opening boxes.

In one of them, she finds Dean's real wife dead, preserved and vacuum-sealed so that there isn't any odor. Just then, Abby spies Dean returning, and tries to warn Bishop, but Bishop left her phone back in the surveillance house.

Dean tries to strangle Bishop -- and he is succeeding since he outweighs her by a good 75 pounds -- when Bishop grabs the scissors she was using to open the boxes and stabs him in the back. He falls, pushing them in even further. Another dead Marine, but this case is closed.

Back at the office, Gibbs asks DiNozzo if he still plans to visit England, and DiNozzo says he will take the trip later. Then he comes clean. While it is true that he is related to Archibald Drummond, the 17th Earl of Trent, Archibald was a scoundrel and died in Newgate Prison. And there are those who think he might have been Jack the Ripper. So much for DiNozzo's dreams of nobility.

Also, McGee sends Bishop flowers, so all is forgiven. Besides, Jake had to travel to Asia on assignment, so he couldn't have made the anniversary trip anyway.

"NCIS" airs Tuesday nights on CBS.