We Untangled the This Is Us Timelines For You
The show switches back and forth between the present day (and sometimes the ambiguous future) and the past to show how the Pearson children's upbringing has influenced their journeys as adults.
While the present timeline stays linear, the stories from the past that center on Jack (Milo Ventimiglia) and Rebecca (Mandy Moore) hop around to different milestones in the family's past.
TVGuide.com is here to help keep track of those important Pearson family moments.
Spoilers are ahead, but you also might want to grab a box of tissues just in case bringing some of these things up causes the tears to flow.
William Meets Randall's biological mother
Jack and Rebecca had sex in the bathroom of the bar after the Pittsburgh Steelers beat the L.A. Rams 31-19.
The date would have made Rebecca eight months pregnant, but both Rebecca and Jack were surprised when her water broke and early deliveries are very common for multiple birth pregnancies.
Rebecca asking William to stay away from his biological son would have a very big impact on Randall growing up, and thus is a key moment in not only Rebecca's and William's lives, but their son's.
The kids are 8 years old when Jack decides to stop drinking and step up to be a better dad, meaning the decision happened after Sept. 20, 1988.
A scene at the end of Episode 5 showed Randall packing up William's belongings into a box while crying.