AMNA NAWAZ: A linchpin of the U.S.-Iran deal signed yesterday relies on two forces not part of the deal, Hezbollah and Israel.

Their deadly back-and-forth continues, with the potential to scuttle the agreement.

Many of the Israeli soldiers are reservists, called up again to fight Israeli adversaries at great personal cost.

Nick Schifrin met one Israeli officer on the border in March and recently spoke with him again after the latest fighting with Hezbollah came close to claiming his life.

NICK SCHIFRIN: For Captain Micha, life has become slower and more quiet.

He was wounded about two months ago fighting for Israel in Southern Lebanon and is now recovering at home outside Tel Aviv.

He holds on to his faith and his desire to return to his men, despite his injury and trauma.

CAPTAIN MICHA, Israeli Defense Forces: My greatest fear is actually to forget.

So I actually don't mind talking about it.

I think it's important.

NICK SCHIFRIN: This is him back in late March patrolling Southern Lebanon through a village emptied by the Israeli military, past the Lebanese homes flattened by Israeli airstrikes.

Before the tenuous and faltering April cease-fire, Israel's campaign in Southern Lebanon was relentless.

The military razed entire towns and villages, pushing out the population.

Lebanese authorities say more than one million have been forced to flee their homes and more than 3,000 were killed.

Israel invaded and occupied deeper into Southern Lebanon than it had in a quarter-century.

Israel says it wanted to put a buffer between Northern Israeli residents and Hezbollah, which had fired thousands of rockets and missiles into Northern Israeli communities, killing dozens of Israeli soldiers and a handful of Israeli civilians.

I visited the border in late March.

Metula, Israel's northernmost town, is where Micha and I first met.

CAPTAIN MICHA: Our job as reservists and our job as the IDF in general is to create a barrier and to create a -- to make sure that we are what is between them and what we consider our enemy.

NICK SCHIFRIN: In the days and weeks after, the military ordered him and his unit to create that barrier inside of Lebanon.

On April the 18th, they were protecting a bulldozer.

CAPTAIN MICHA: The bulldozer went over an explosive device and basically took out of the ground and all the explosive device and it exploded on our men.

It was a massive explosion.

Initially, I got injured.

I have many pieces of shrapnel in my legs.

And, initially, I didn't realize -- I mean, I have got -- I had immense pain in both my legs, but I was still able to run backwards and get on the radio and see how my soldiers were doing, because I didn't actually realize that something hit me.

NICK SCHIFRIN: One of his soldiers was killed that day, Sergeant First Class Lidor Porat, who was 31 years old.

CAPTAIN MICHA: He actually volunteered to come to my unit.

He was in a -- he wasn't in as much of a combat unit, as we were.

And about a year ago, he had a friend that was in my platoon, a soldier of mine, and just as life would have it, he ended up losing his life in the battlefield.

NICK SCHIFRIN: The bomb tore through one of Micha's arteries and multiple veins.

He survived thanks to quick care.

His is a soldier's stoicism.

CAPTAIN MICHA: The actual moment itself, in a way, was a shock, but also it's what you come to expect when you go to war.

I think the thing about war, and when you go into enemy territory, is you know that people are trying to harm you and kill you, and we were evacuated pretty quickly.

NICK SCHIFRIN: Hezbollah has made Israel's invasion of Southern Lebanon even more deadly, thanks to drones.

Hezbollah videos show first-person view or FPV drones targeting Israeli soldiers precisely.

These drones are often operated using long fiber-optic cables, the same technology I filmed in Ukrainian trenches, with Ukrainian soldiers targeting Russians.

CAPTAIN MICHA: We have known that they had these kind of capabilities for a while, and I think it was a matter of time until it became so popular to them in such a mass scale.

If you would actually see the numbers of how many drones are hitting or trying to attack Israelis every single day, and the number of casualties and injuries, I think we will see and we can see that slowly, slowly, the army's getting better at adapting.

NICK SCHIFRIN: But Micha is a reservist, and the Israeli army and society have struggled to adapt to sending reservists to war repeatedly since the October 7 Hamas terrorist attack.

Of 900 days after that day, he deployed more than 500 when we first met in March.

CAPTAIN MICHA: The impact of these wars since October the 7th has been immense on Israeli society, especially on reservists, really straining the fabric of Israeli society.

So I think that there's nothing we have felt more than that.

If I have a soldier, that any of my soldiers will come up to me and tell me, "Micha, my wife is finished, I need to go home," so we will send them home, because there is no point to protect our home if there's no home to go back to at the end of the day.

My mom has four reservist sons.

She hasn't slept in about 10 years.

I got married shortly before October 7, and I have been 500 days in reserve, so, I mean, I have seen my soldiers a bit more than I have seen my wife since I have been married.

The first thing I told my wife when she came and saw me after the surgery, it was 3:00 a.m., and she came into the ICU, and she asked me how I am.

I told her that -- the first thing I told her was that: "I'm sorry, but once I'm recovered, I'm going back to the unit."

So she wasn't very happy.

NICK SCHIFRIN: And why do you want to go back to your unit, despite the risks?

CAPTAIN MICHA: Because the risks have always been there.

It's not a new risk.

Someone needs to be on the front line, and if all of us will say that another person will do it, then no one will be there, so it's my time.

And it's my time now and it'll be my time in a few months when I fully recover.

NICK SCHIFRIN: But he's planning a future for after the war.

He's studying to practice law.

Until then, he checks his phone for news from his men.

His recovery depends on theirs as well.

For the "PBS News Hour," I'm Nick Schifrin.