(NBC News) – On an all-new two-hour “Dateline,” a romantic Mediterranean cruise was intended to rekindle the love between Micki Kanesaki and her ex-husband Lonnie Kocontes, but when Micki vanishes, an investigation reveals secret recordings, a surprising star witness, and an undercover hitman.

Here is a preview of Josh Mankiewicz’s report:

The call came in the middle of the night. It was their friend, in a panic.

SUSAN MCQUEEN: Lonnie was in Napoli, and, Micki had gone missing off the boat. And that’s where it started.

JOSH MANKIEWICZ: And what did you think?

SUSAN MCQUEEN: That was a take a — to the count of three kind of, you know, repeat all of that, let me hear it one more time type of thing.

No matter how many times she heard it, it just didn’t make sense.

SUSAN MCQUEEN: You, you think of all of these things. Everything starts rushing through your head.

Except this was clearly true.

BILL PRICE: I just saw disaster happening, in a foreign country.

SUSAN MCQUEEN: You say, this, this can’t be. This can’t be.

BILL PRICE: I knew it in my heart. There’s got to be another explanation.

There was an explanation, all right. It just wasn’t the one anyone was expecting.

Watch “Dateline” tonight on NCB4 at 9 p.m., right after two encore episodes of NBC’s new comedy, “Mr. Mayor.”

About ‘Dateline’

“Dateline NBC” is the longest-running series in NBC primetime history and is in its 31st season. Dateline is anchored by Lester Holt and features correspondents Andrea Canning, Josh Mankiewicz, Natalie Morales, Keith Morrison and Dennis Murphy.

Dateline is the #1 Friday newsmagazine and reaches more than 17 million people every week through its broadcast, and millions more through its social media platforms and podcasts.

The stories range from compelling mysteries to powerful documentaries and in-depth investigations. When major news breaks, they go to the scene, putting the pieces together to bring the viewer the full picture. And in every story they tell, they help the real people who lived the events share their journeys with the viewer.