10 This Is Us Tissue Moments: Cassidy's PTSD Triggers a Crisis and Kevin Finally Finds His Purpose

Each season, the writers set aside three episodes that will focus entirely on one of the Big Three. But the actions within them happen simultaneously, as they each take stock of their lives in the now, and reflect on how it relates to pivotal experiences from their youths.

Understandably, the triggering moment for this season's "Trilogy" is Rebecca's powerful speech to her children demanding that they "not make your lives smaller because of me." The first to take that message is Kevin, who is as impulsive as ever in his reaction.

This week's story may be Kevin-centric, but it's the supporting characters around him who really shine. After feeling challenged as a parent, he takes Kate's advice to parent with confidence and decides to travel with the twins to check on construction at the cabin.

This brings him back into the circle of Nicky and Edie -- who remain absolutely delightful -- as well as Cassidy and her son Nicky. Cassidy took him up on the offer to serve as foreman, which brings her back into the fold, as well.

What follows was an unexpected exploration of the traumas of war in a way that saw Nicky's Vietnam experiences parallel Cassidy's far more recent ordeal. The PTSD both endured is so raw and so real, and while Nicky has made tremendous progress through the course of the series, Cassidy is still in a pretty dark place.

We can't say enough about the incredible work of Jennifer Morrison in a key scene deep into the episode where she finally opens up a bit about her experiences over there with Kevin. It was so palpable and raw and painful. The chemistry between her and Griffin Dunne, who was also stellar with his compassion and grace, is second to none.

Through that entire segment, Kevin was there but he did not say a word. It was good that he did this, on guidance from Nicky, because it was the right thing to do both for the character and the actor, as it allowed Morrison and Dunne to really shine.

As we do every week, we're going to single out the show's most powerful moments, scoring them by how many tissues we tore through just to watch them. Believe us, these are happy tears of anguish.

"He Slashed My Tires, Help Me"

Nicky has come such a long way since we met him as a broken man in his trailer staring at  a gun with thoughts to use it, he deserves this woman and this happiness. Edie is an absolute delight and we love that she can go toe to toe with him in sarcasm. They're a perfect pairing, and she brings out such a light in him. Nicky spent so many years in the dark, his is a story of how it's never too late to change your path. If you're ready and you put in the work, there can be brighter days ahead for anyone. They make us smile in the same way we used to smile about Kate and Toby (le sigh).

1 tissue (they just make us happy)

"I Wanna Jump Off the Diving Board"

In our earliest flashback, we have young Kevin with the family at the pool. As always, he's eager and impulsive and seems to think things should just work out for him without any work or effort. He doesn't care that he doesn't now how to swim. He wants to jump off the board and touch the drain at the bottom. When Jack tells him he has to prove he can swim first, and Kevin struggles, he later accuses Jack of trying to drown him. From a young age, Kevin has blamed others for his problems and thought he could shortcut his way to the things he wanted. He's never bothered to slow down and put in the work.

2 tissues (some problems start so young)

"I Don't Belong in the Deep End"

In our mid-flashback sequence, we have the kids shortly after Rebecca found out Miguel was moving away at Thanksgiving. Randall and Kate follow Kevin out to the same pool, now drained and about to be torn apart. Finally, with the water gone, Kevin could reach the drain, but it feels empty. Drunk and emotional, he declares that he's not worthy of the deep end because he has no depth. This is a revelation that Kevin seems to have over and over and over again throughout his life, and yet he never quite knows what to do about it. Or maybe it's just that it takes too much work to do anything about it, and this way is good enough, right? Instead, he cycles into self-loathing over the work on himself that he won't do.

2 tissues (self-awareness does not always lead to change)

"You Ever Feel Like You're Performing?"

For proof, Kevin decides to bother a poor man in the hospital waiting room (we told you there was an accident tonight!) about how he's there doing the right thing. But is he doing it because it's right and he doesn't want to be wrong, or is he an innately good man who just does the right thing. Basically, Kevin has "imposter syndrome" about his own life, about being the good and kind man he wants to be, that he believes his father to have been. Jack always seemed to just know the right thing to do. Kevin, meanwhile, has people telling him all the time what to do. Nicky tells him how to be around Cassidy, Kate tells him how to be as a parent, Rebecca tells him how to live the rest of his life and he sets out to do it. But what does he want? Who is he really?

2 tissues (it's hard to know anything when you doubt your very self)

"You're Gonna Be a Screw-Up for a While"

Kate has unconditionally loved Kevin his whole life. She has supported him to the detriment of her own friendships and relationships, at least until recently. But she has also been very candid and honest with him. The Big Three has this ability to be very real with one another in ways that almost seem cruel, but because of their "triplet" status, they allow it from one another. Kate's insight as a young adult about Kevin was absolutely right. He screwed up his marriage because of impulse control and he's learned basically nothing from that. Instead, he's drinking and out making more bad decisions. Kevin has only begun to screw up his life!

2 tissues (the brutal honesty of siblings)

"You're Exactly Like Him"

Once again, it's the show's unsung hero to the rescue. After little Kevin feels like Jack tried to drown him at the pool, Rebecca comes to save the day with loving words and an Orange Dreamsicle. Young Kevin pushes back at the idea that he's anything like his father, but Rebecca knows that the two of them are so much alike. Both want to be good, but both are so afraid that they're not. That fear of not being enough drives them into their addictions, which they then try to hide so as not to throw off that facade that everything is great. And now, things come full circle after Kevin discovers that Cassidy hired professional construction workers who are all veterans to build the dream cabin.

3 tissues (the apple doesn't fall far)

"I Think We Should Hire a Few More"

After Nicky gave him a hard lesson in the challenges veterans face after they come home from war, no matter how long ago it was, Kevin gains a new understanding and appreciation for that struggle. Cassidy opening up a little about her own experiences after all that he'd learned over the years from Nicky, helped him to understand a bit more. But truthfully, he'll never understand, which is why it was so important he chose silence when Cassidy finally opened up to him. He could be there, but he should not try to convince her he understands, because he can't. She was able to break down fully with Nicky because he does understand. But what Kevin does understand is that it's hard for veterans when they come back, and maybe there is something he can do. He can't fix Cassidy but that's what his instincts tell him to do. So instead, he brings us full circle to that sketch from Kate's wedding day of "Big Three Construction." What if this was a company that hired a veteran labor force? And just like that, Kevin becomes even more like his father, fulfilling the kinds of dreams that would definitely make Jack proud -- and in Jack's own field.

3 tissues (it doesn't fall far at all)

"You Find Out the Hard Way"

When Kevin got a call in the middle of the night after their great evening of playing games and laughing, he thought the worst. Cassidy was in a car accident, and his mind went straight to her relapsing into alcoholism. But Nicky had a far keener understanding. Cassidy had that thousand-yard stare all night, and she made a point of not sitting with her back to the door. Her demons were haunting her, and Nicky feared the worst. And as he pointed out to Kevin, you have to be watching and sometimes even that's not enough. If Cassidy decides that it's all too much and she can't' live with what she had to do while over there, she's not going to take out an ad in the paper or announce it publicly. She's just going to be done.

4 tissues (sometimes there are no signs at all)

"I've Been That Before"

As part of that keen reminder to Kevin that he is an outsider in this situation, Nicky reminded him that he can see what Cassidy is going through in this moment because he's been there. Kevin found him with a gun on his table in front of him five decades after Vietnam ended. The wounds on the psyche can stay as fresh as the day you got them forever. Nicky compassionately gives Cassidy the name of someone at the VA to talk to. For all of Kevin's good intentions, and for the fact that he was ultimately able to help Nicky (though it was a messy process), it's wonderful for Cassidy that Nicky is a part of her life right now. She knows what he's been through, and she can see how easy his happiness is. She may not know how to find it for herself right now, but she can see that it's possible, and that gives hope.

4 tissues (some wounds never heal fully)

"I Didn't Fight the Sleep"

When Kevin fought against all of his instincts to pry and ask questions and told Cassidy in her hospital bed that he would just sit there, that's what she needed. The doctor had already told Kevin and Nicky that she basically hit a pole head on. She talked a little bit about what she did over there and how it haunts her. She would convince people that she could save them from the warzone if they gave her intelligence. Sometimes she meant it, sometimes she didn't. More often than not, she was not able to honor her word. That and the loss of friends over there and since coming home haunt her. More than she was probably able to express haunts her. And despite having a 12-year-old son, who was with them at the cabin, when she couldn't sleep and went for a late-night drive only to suddenly start getting tired, she "didn't fight the sleep." Instead, she accelerated. It was heartbreaking to hear and there is nothing that Kevin can do to fix that. He can't unmake her experiences, he can't make her mind stop reliving them. But if she's open to it, there is a process that can help her, which is what Nicky tried to initiate by giving her that contact information. For Kevin, it was a sobering realization that he can't just fix everything, and he can't just will things to work out.

5 tissues (some wounds haunt)

"This Is Us" continues every Tuesday at 9 p.m. ET on NBC.