We'd already traced Iliza Shlesinger's paternal roots from Poland to New York, showing how her great-grandmother, Esther, came to America in 1921 all on her own.

Now we turn to a tragic side of this story.

When Esther emigrated, she left five siblings behind, and they would soon face an unimaginable ordeal.

On September 3, 1939, the German army entered the Polish town of MBawa, where Esther's brother, Lipa, was a textile dealer.

Within a year, the town's Jewish population was confined to a walled-in ghetto.

This was never talked about in your family?

No.

Okay, now you have a younger brother, Ben.

I do.

What do you imagine it must have been like for Esther, knowing that her sibling was in so much danger?

Horrific.

I can't, I know that feeling when your sibling's in danger, and you feel helpless, especially from like an ocean away.

So I can't begin to imagine this.

Mm-hmm.

And I don't think I want to.

Could you please turn the page?

Sure.

That is the MBawa ghetto.

Mm.

Yeah.

What's it like to see that, to think that you had a relative who was there?

You almost, when you look at pictures from history of atrocities committed against your people in particular, there's always that pull, but I never thought I had any actual connection because I didn't know any of the history.

It was abstract.

Yes, so I have to like sit with that.

I understand that.

- Yeah, of course.

- Yep.

The MBawa ghetto was essentially a death trap.

Residents had to live in pigsties and barns, and in November of 1942, transports began leaving for Auschwitz, where Esther's brother would meet a terrible fate.

"Lipa Szonek, Jewish religion, resident of MBawa, passed away on the-" passed away, "on the 11th of January, 1943 at 12:45 in Auschwitz.

The deceased was born on the 15th of July in 1901 in Raci.

Cause of death, myocardial degeneration."

What's it like to learn that you do, in fact, have a tangible blood connection to the Holocaust?

Ooh.

It was already so real, and so now it's... palpable.

You already feel that... you already feel it so much, and like it's like a horrific missing piece.

Then, of course, you read something like this, and you're like, why is there even, like the fact that there was even a doctor 'cause they, you're murdered.

Right.

Your heart didn't degenerate.

Of course, it degenerated 'cause you were starved and... Sure, of course.

You were murdered.

I can't believe these monsters even wrote it down, but because they're psychotic, they wrote everything down.

And remember, your great-grandmother, Esther, is alive in America at that time.

I mean, I guess we're all alive because someone was lucky.

- Right.

- You know?

Yeah.

Wow.

That's just so hard to look at.

Even if it wasn't my family, like these things are always very painful and hard to read.

Yeah.

Okay.

We now set out to see what happened to Esther's other siblings.

We discovered that her brother, Abram, left Poland in 1931 and settled in France, where he married and started a family, but that didn't guarantee his safety.

Nazi Germany invaded France in 1940, and the country soon faced the same horror as Poland.

Roughly 20% of France's Jewish population was exterminated.

So we wanted to see what happened to Abram and his family.

Please turn the page.

I don't think I want to.

Iliza, this is a passenger record for a list of passengers who arrived in New York from France in November of 1955.

Abram survived the Holocaust.

Okay.

What's it like to learn that?

That's the good side of the story.

- Yeah.

- I know you thought, "Oh my God, he's gonna take me through Auschwitz again."

I was like, "I don't wanna hear that."

Just, okay, wow.

Can you imagine Abram and Esther's reunion?

- Oh wow.

- Oh my God.

Haven't seen each other in, what, since she was 22, so.

Yeah.

And to know that they lost at least one sibling that I know of, as of now, wow, wow.

According to one of Abram's daughters, his family survived the war by hiding with a French farmer.

Ironically, Iliza's grandfather, Benjamin, joined the United States Army during World War II and was stationed in France, meaning that he was unwittingly close to the site of an enormous family tragedy.

Do you think he knew he had immediate family in occupied Poland?

I don't know.

Relatives who were being locked in ghettos and dying in concentration camps?

I don't think he did because no one ever said anything, like, why wouldn't you say that to your family?

My nana never, I mean, that's her husband, but no one ever said anything.

Maybe he didn't know.

Maybe.

Oh, he didn't know.

And he was in France.

And he was in France too.

Wow, what a complex... Yeah.

Thing.

Contingency, accident.

Yeah.

Just, you make a choice, have no idea.

Unintended consequences.

Sure.

Unintended consequences of leaving, unintended consequences of staying.

'Cause some stayed and they were okay, and then to have a relative be there, fighting for what's right while, I mean, it's happening in just two different worlds - right next to each other.

- Right.

The complexities of war playing themselves out in the drama of one family.

Yeah.

What's it been like for you to learn about your father's family in this kind of detail?

Mind-blowing because I didn't know any of this, and I don't think my dad knew any of this, and he's kind of like the last of his family, at least, I thought, I don't know what the kids that these people went on to have, but I always thought I had a very small family that like, almost came out of nowhere.

Mm-hmm, mm-hmm.

And it's such a gift to be given any family history, just so you can kind of figure out your place in time in the context of all these people who were brave and who died.

It's incredible.