Did 'This Is Us' Reveal the Real Cause of Jack's Death in 'Vietnam'?

Meaghan Darwish
Spoiler Alert Ron Batzdorff/NBC

In this week's fourth episode of Season 3, This Is Us gave fans a new perspective on Jack's (Milo Ventimiglia) life via his time serving in Vietnam.

Throughout the aptly-titled "Vietnam," fans got glimpses into Jack's childhood, his relationship with brother Nicky (Michael Angarano), and, perhaps most importantly, learned about a previously unknown ailment of the Pearson patriarch. Suddenly we're brought back to Jack's eventual death due to one important detail — his heart condition.

'This Is Us': 'The Only Thing That Matters' to Jack (RECAP)

'This Is Us': 'The Only Thing That Matters' to Jack (RECAP)

This week's episode was the tale of two brothers and so much more.

In the show's second season, the mystery surrounding Jack's deathseemed to have been solved — he'd died of a supposed widow-maker's heart attack following smoke inhalation from a fire in the Pearson family home. Then, in last night's episode, we see Jack getting a physical before joining the army. His doctor then reveals that Jack's heart condition should stop him from enlisting.

Based on a flashback in the episode, tachycardia is something Jack's dealt with since childhood — an abnormally fast heart rate that, when left untreated, can cause serious complications later in life. Still, prior to the house fire, there was no indication the father of three had heart issues, so it's assumed that he never revealed his condition to Rebecca (Mandy Moore) or the kids, judging by their shock over his heart attack.

THIS IS US -- "Vietnam" Episode 305 -- Pictured: (l-r) Michael Angarano as Nicky, Milo Ventimiglia as Jack Pearson -- (Photo by: Ron Batzdorff/NBC)

Angarano and Ventimiglia

But knowing what we do now, maybe the cause of death cited for Jack was wrong — perhaps it was a complication caused by his tachycardia.

Meanwhile, Jack's brother Nicky, who we know dies during the war, will meet a different fate — and new star Michael Angarano isn't sugar- coating his character's death.

"I think it’ll be a little bit surprising how dark and sad some of this stuff is, because this was a very dark and sad and violent war," Angarano told Deadline. "And so the storyline feels like it’s very much that…I think a lot of the story is how these two men deal with the same war in very different ways."

'This Is Us': See Jack's Brother Nicky in 'Vietnam' Sneak Peek (PHOTOS)

'This Is Us': See Jack's Brother Nicky in 'Vietnam' Sneak Peek (PHOTOS)

The latest episode will feature the Pearson patriarch's time serving overseas.

Much like Jack's death, Nicky's is just as under wraps. Still, from his apparent drug (pill) use, his demise could be unrelated to combat. If this show proves anything, it's it's hard to predict the full story.

This Is Us, Tuesdays, 9/8c, NBC

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