The 'This Is Us' Season 4 Episode 6 Promo Teases Toby & Kate's Eventual Breakup

This Is Us Season 4 is a critical fulcrum in the NBC series run. The show is set to run six seasons altogether, with the first three seasons as a climbing of the roller coaster. These early episodes of Season 4 are just as the cars crest the very top, and it's all emotional loop-de-loops from here on out. The This Is Us Season 4 Episode 6 promo suggests that one of the biggest downhill slides is about the begin, as the inevitable divorce for Toby and Kate draws ever closer. Warning: Spoilers for This Is Us Season 4 follow.

Fans have seen the future in at the end of This Is Us Season 3, and it doesn't look good for Toby and Kate. Though no one ever says they've divorced, all signs point to it. From the lack of wedding rings to Randall's relief that Toby showed up at all, it seems like he's no longer beholden as her spouse to lend support. (Not to mention Toby's shock at Kevin's house, which let audiences know it was his first time being there. If he and Kate were still married, there's no way that would be the case.)

But when does their marriage start to crumble? This week's trailer for Season 4, Episode 6, "The Club," suggests the answer is very soon.

But Kate and Toby aren't the only stories this week. The trailer also shows flashbacks to Randall's preteen years and a trip to the golf course, as well as Kevin and Cassidy's continued friendship. Then there's the synopsis, which throws in two more storylines:

Kate and Toby try to make time for their marriage. Jack attempts to prove himself to Rebecca's father. Randall struggles to find his place with the other councilmen.

Season 4, Episode 5, "Storybook Love," ended with Randall refusing to consider therapy, even as he pushes Tess to go for the same anxiety issues. Though the synopsis doesn't come out and say it, Randall's struggle with his fellow councilmen will almost certainly tie back to his ever-more-frayed nerves.

Jack's "proving himself" to Rebecca's father is also interesting. The teaser shows one flashback to Jack's discomfort at a country club golf course. It looks like this might be a flashback-within-a-flashback. Jack's experience with Rebecca's father in the 1970s color his experiences with Randall in the 1990s, which, in turn, effects Randall's comfort around his fellow politicians.

As for the Kate and Kevin cliffhangers at the end of "Storybook Love," fans are going to have to wait for to go back to the year 1998 and both their impending disaster relationships. Speaking to Entertainment Weekly, producer Isaac Aptaker says that timeline is being backburnered for a bit.

[W]e’re moving away from this timeline for a bit that we’ve been in now for back-to-back weeks. We have so many different decades of this show that we have to service and give attention to. But yes, deeper in the season, we will certainly be getting back to what it looks like to be 18 and unemployed and married in New York.

This Is Us continues on Tuesdays on NBC at 9 p.m. ET.