The Penultimate Twist In This Is Us Is An Emotional Doozy

This Is Us started with the premise that strangers around the globe share the same birthday and don’t even know it. The people from all walks of live can affect our own lives, and no one would be the wiser. Although the original twist was that the “four strangers” who share the same birthday in the first episode are actually all members of one family, the series has never abandoned the theme of random connections, from Esther Pariente and Nasir Ahmed in the show’s ode to Zoom calls to Marcus Brooks in This Is Us’ penultimate episode.

Warning: Spoilers for This is Us Season 6, Episode 17 follow. This Is Us’ penultimate episode, “The Train,” was one viewers have been dreading — it was time to say goodbye to Rebecca. But alongside the story was the story of the Brooks family, who were introduced driving home together on a January night. The youngest, Marcus, and his older brother were roughhousing in the backseat. Despite their father trying to keep his eyes on the road, an oncoming car lost control at the wrong moment. An unbuckled Marcus was severely injured in the crash.

Thankfully, the episode was quick to reveal a grown-up Marcus in the present day, making it clear he survived in the aftermath. Considering Deja’s pregnancy was a significant feature of the episode, many fans immediately started guessing Marcus was the father of Deja’s unborn child. It’s a sensible reaction: Deja’s going to medical school and said her boyfriend is always working. Meanwhile, fans were watching grown-up Marcus staying late in a lab, struggling to find a cure for cancer. But that theory was squashed when Malik was revealed as Deja’s boyfriend. Upon getting her text telling him she was pregnant, he rushed home and proposed, saying he’s been in love with her since he was 16. It was everything fans wanted from that ending.

But then, who was Marcus?

The Brooks family’s connection to the Pearsons became a little clearer when present-day Marcus met up with his siblings, lamenting his inability to cure cancer on the first try. His sister and brother reminded him of their dad’s favorite saying... something about there not being a lemon so sour, you can’t lemonade. The three laughed and wondered where their dad got the saying from, and whether the saying even makes sense.

Longtime This Is Us fans know the phrase well: “There is no lemon so sour that you can't make something resembling lemonade.” It’s what Dr. K said when one of Jack and Rebecca’s triplets didn’t survive birth, and it’s clearly something Jack kept top of mind. As the Brooks father waited to hear if Marcus would make it that night in January, he ran into a man in red flannel, whose house had just burned down and was waiting for the docs to check him out for smoke inhalation. Jack only talked to Brooks for a few minutes over the coffee machine before he subsequently perished from a massive heart attack, but it was long enough to impart those words of wisdom. Soon after, a flatlining Marcus miraculously survived the exact moment Jack passed away. Jack’s doctor had gone off to help Marcus just as Jack’s heart gave out.

Using the work he’d done to find a cancer cure, Marcus went on to create a possible cure for Alzheimer’s. The cure won’t come soon enough for Rebecca. However, it’s a big step in making sure families like the Pearsons never go through what they did.

Some will believe Jack’s life ended so Marcus could live, or they’ll argue Jack’s soul lives on in Marcus. Whether that’s true or just a coincidence, when two strangers ended up in a hospital together, their lives touched.

This Is Us: The Final Season has one more episode to go, on Tuesday, May 24, at 9 p.m. ET on NBC and streaming the next day on Hulu.