During episode 5 of season 2 of "This Is Us" another piece of Jack's past was revealed in the last seconds of the episode. Jack Pearson was revealed to have a younger brother, Nicky, who up to this point has not even been hinted at. Jack's urging throughout the episode for Kevin and Randall to get along is not only show as coming from a place of fatherly love, but also from a place of brotherly love.

Brother is the theme

The episode begins with Jack taking both sons on a camping trip, similar to the one his own father took him on as a child as revealed through a flashback of Jack's childhood.

His childhood trip started with his father pulling into a tavern and leaving Jack in the hot car to wait for him. He repeatedly tells himself that his father will come back while watching his father sitting inside drinking a beer. As the episode comes to a close, Nicky pops up from the backseat of the car where he had been sleeping. This reveals that Jack is not an only child, but rather a big brother. Nicky wondering what is going on asks his brother where their father is and when he'll be back. Jack reassures him that even though their father won't be back for a while that he is not going anywhere. We then see Jack holding a picture from his war days that shows us that Nicky was with him in Vietnam, adding another layer to the mystery.

Jack's secret past

Much of Jack's past is shrouded in secrecy with only small details being revealed to fans so far. We have been told about his father, who is extremely ill at this point, and about how he came to meet Rebecca. Other than these facts though, Jack's history is still very much a secret.

Is Nicky the reason that Jack pushes so hard for Kevin to be kind to Randall?

Does Jack feel like he failed Nicky? Making this his reasoning for wanting his sons to always have each other's backs maybe he sees himself in Kevin and that worries him. During the camping trip, Jack pulls Kevin aside and tells him that he needs to treat Randall better and that they should be able to depend on each other more than anyone else in the world.

It makes one wonder if he is speaking from experience, having let Nicky down at some point that may have ended in disaster.

This twist brings up numerous amounts of new questions about Jack's history, as many "This Is Us" twists do. Did Nicky make it back or was he lost in the war? Does part of the reason Jack hates his father so much have to do with Nicky? Does he feel responsible for what happened to Nicky? Having never met Jacks father does Rebecca know about Nicky and what happened to him? Is Nicky part of the reason that Jack starts drinking so heavily? A problem that Kevin is starting to have as well due to his knee injury. It doesn't look like we are going to get any answers, as to what happened all those years ago, soon though.

The preview for episode 6 shows that we will be seeing the triplets during their 20's, a time that we have not seen them in yet. It also previews flashbacks to a Halloween night from when the triplets were younger, but nothing about Jack's past. It is safe to assume that this mystery, like Jack's death, will not be solved for some time.