The Big ‘This Is Us’ Season 4 Finale Theory Will Make You Rethink Everything

This Is Us Season 4 began in a manner that shocked the fandom. After three seasons of focusing on the Pearson family, this season's premiere brought in characters fans had never met before: Cassidy, Malik, and Jack. By the end of the hour, the former two's paths had crossed with the Pearsons, Cassidy meeting Uncle Nicky and Malik meeting Deja. Jack turned out to be the adult version of Kate and Toby's son. Since then, the show has returned to normal, but a This Is Us Season 4 finale theory suggests the end is just the beginning.

Season 4's premiere episode was entitled "Strangers." It was an accurate description of the hour, as fans found themselves sitting with three total strangers, who were suddenly starring on the show in place of their beloved Pearsons.

But as the poem goes, "There are no strangers here; Only friends you haven't yet met." By the end of the first half of Season 4, none of these characters were strangers anymore. Malik and Deja were in love, and all parents had given their blessings. Kevin and Cassidy struggled towards sobriety together. Though they did once fall into bed, they decided to part as friends, and Cassidy went home to try her marriage again. As for Adult Jack, fans are wild for more of his storyline.

But these new strangers have faded away in the second half of Season 4. Cassidy is gone, Malik and Deja have disappeared in the face of Randall's need for therapy. Adult Jack only appears sporadically. But fans have a theory that the Season 4 will come full circle before all is said and done. As revealed by TVLine, the Season 4 finale is entitled "Strangers, Part 2."

The finale will arrive with a lot of loose ends to tie up. For instance, fans know by the time the Season 5 premiere rolls around in September, Kevin will be engaged to his pregnant fiancée. Randall will not be talking to his siblings or his mother. And Kate and Toby will not be celebrating her birthday together.

With so much Pearson drama to get through, how does another episode of "Strangers" fit in? For some, it's conclusive proof that the pregnant fiancée isn't Kate's BFF Madison, who Kevin also slept with this season. It's Cassidy, who will return to the series as a regular from here on out. It also could affect Randall. If Deja and Malik's relationship goes sideways, it could be the straw that finally breaks the camel's back in his anxiety.

But it could also be that new strangers come into the lives of these characters. Perhaps Toby finally meets someone else and cheats on Kate? Or maybes Jack, far in the future, will tell the tale of how his parent's marriage eventually ended.

The This Is Us Season 4 finale airs on Tuesday, March 24, at 9 p.m. ET on NBC.