5 Theories About the Mark & Kate Mystery on 'This Is Us'

Meaghan Darwish
NBC

[Warning: The below contains MAJOR spoilers for Season 4, Episode 5 of This Is Us, "Storybook Love"]

This Is Us has introduced its fair share of mysteries over the seasons and in October 22's "Storybook Love," a new one reared its head in the episode's final moments.

What could it be this time? Well, teenage Kate (Hannah Zeile) has a new boyfriend, but there's something up with Mark (Austin Abrams), as evidenced by the present-day Pearson's (Chrissy Metz) reaction to a Polaroid featuring the couple.

"I was trying so hard to hold it together that year after your father died, and I wanted to believe so badly that you kids were happy," Rebecca (Mandy Moore) said to Kate in the final scene. "I didn't see what was happening." Before Rebecca can say any more on the cryptic situation,  Kate added, "I didn't see what was happening either."

"Fans should have a healthy amount of concern," executive producer Isaac Aptaker told Entertainment Weekly. "There's something ominous looming there, the way that Rebecca and Kate are speaking about that relationship in present day. And although he seems like a sweet guy now, it certainly seems like that did not end well for Kate."

So, considering this new mystery, we're breaking down a few theories about what it all could mean below.

Manipulation

(Credit: NBC)

The first time that Kate and Mark meet, it's in the record shop where he hires her. But before the job offer comes, she opens up about her recent family woes, including her burned-down house and dead father Jack (Milo Ventimiglia). Could Kate's openness about her situation make her a target for manipulation? Now that she's working with him, it puts Kate in Mark's orbit constantly, leaving her ear open to Mark's influence.

Addiction

(Credit: NBC)

Kate struggles with overeating in both the past and present timelines, with the teen version still grappling with Jack's loss. Could potential relationship drama with Mark cause her to spiral even more? There's clearly a drastic change ahead for the character as she'll face significant physical changes, and Mark could very well be a catalyst for this.

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Naivety

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We don't want to brand Kate as a naive individual, but it is mentioned in the episode that Mark is a few years older than her. Perhaps their age gap could be detrimental to the success of their relationship moving forward. It's clear that Mark has a strong personality, he's not afraid to take and do what he wants. And while it seems tame now, it could turn into something ugly with his younger girlfriend.

Boundary Issues

(Credit: NBC)

In the show's most recent episode, Mark shows up at Kate's new house and claims that he didn't want her going through the tense family dinner alone. She says that's sweet but also "creepy," and while it seems like a throwaway comment, it shouldn't be ignored. Kate never asked Mark to come and he just did, along with introducing himself as Kate's boyfriend. There's certainly some kind of disconnect there, which makes the situation more concerning.

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Abuse

(Credit: NBC)

Kate's emotional and mental wellbeing has been a rollercoaster ride since the beginning of the show, and it's clear this relationship will only make it more turbulent. Could Mark traumatize Kate so much that she's left even more broken than she was following Jack's death? It's looking to be that way, and as much as we wish it won't be that way, Rebecca's words might imply a level of abuse took place during Kate and Mark's time together.

For now we can only speculate, so tune in Tuesdays to see how their story unfolds.

This Is Us, Tuesdays, 9/8c, NBC