If you think that Jack Pearson's death in the Crock-Pot fire is the most tragic thing about This Is Us, you're wrong. The most heart-wrenching plot line about the Pearson family is actually Nicky's backstory on This Is Us, told through a series of flashbacks in "One Small Step." It also explains a lot about Jack (as well as raise some questions). Hold your snowglobes tightly, my friends. It's about to get sad.

We already know from Season 4 that Nicky was discharged from the war for "psychiatric reasons" after an incident that led to the death of an innocent Vietnamese boy. Jack, who was inexplicably stationed in the same village as his brother, was horrified at the fallout and told his brother that he was "done" with him, going as far as to tell his family, and Rebecca when he first met her, that Nicky had died in the war.

Any armchair therapist could tell you that Nicky clearly suffered from depression and/or anxiety long before the war. In the years immediately after, he was only more tortured, longing for the connection with his brother that he had lost. It makes the fact that they never reconciled even more heartbreaking.

It also makes you ask why Jack made the choice to pretend like his brother was dead. The two were close before the war. Jack was Nicky's number one cheerleader (he even bought him luggage!). One conversation could have changed everything, or at least could have possibly led to a life of less hurt for Nicky.