Kevin & Randall's Feud On 'This Is Us' Might Stem From The Time Capsule At Their Cabin

THIS IS US -- "Lights and Shadows" Episode 410 -- Pictured: Sterling K. Brown as Randall -- (Photo b...
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Now that another Big Three episode trilogy has come and gone, it's time for This Is Us to turn its attention back to another mystery that has been plaguing viewers for months: what happens to make Kevin and Randall no longer on speaking terms by the time of their 40th birthday? Many believe it has something to do with Rebecca's health, however, a new theory about Kevin and Randall's feud on This Is Us suggests that it nothing to do with their present day lives and everything to do with the past.

The promo for Tuesday's episode "The Cabin," reveals that Kevin, Kate, and Randall will use their visit to the cabin to dig up an old time capsule that they buried years and years ago. And considering that this series loves to throw a few curveballs our way, there's a solid chance that whatever they unearth may not be as fun as they intended it to be. After all, that's bound to happen when you start digging things up from the past, both metaphorically and literally. In fact, it's prompted some Twitter users, like @caramelcoat8dme, to predict that whatever is in this time capsule will be the cause of Kevin and Randall's upcoming fight.

This Is Us loves to connect storylines in surprising ways, so perhaps it'll somehow connect back to the flashbacks surrounding Marc's visit to the cabin with Kate. Did something happen that night that not everyone else knows about that one of them buried alongside (or within) the time capsule? Or maybe the time capsule brings up older issues even further back in the past when they were much younger and Jack was still around. (He is, after all, the one who introduces them to the concept.) Did Randall or Kevin take something of their dad's and put it in the container without letting the other know about it? Did one of them write a letter complaining about the other? It could be anything.

Given this show's love for a good plot twist, it seems impossible to predict what happens to make their brotherly friendship fall apart. Though, whatever ends up happening, Justin Hartley promises that it's going to be a major falling out unlike anything viewers have seen before.

"It's big. No, it's big, big. It's more than a misunderstanding. I think it's a philosophy," the actor teased during a recent interview with Entertainment Tonight. "This is not like we're going to argue about something. This is two men, two brothers each taking a stand that suggests that if they don't bend, the other one will not be in their life. I mean, it is a big deal. It just gives them... it's a big deal."

The Pearsons have recovered from a lot over the last several seasons. Let's just hope Kevin and Randall's connection is strong enough to defeat whatever obstacle ultimately comes their way.