The events surrounding first birthdays or births in three different time periods are presented. In the past, Jack and Rebecca are not only celebrating Jack's thirty-seventh birthday with a modification to their usual routine, but the first birthday of the Big Three. It can't help but be a bittersweet occasion for both of them, they turning to an old friend for advice in how to deal with the bitter in light of the sweet. In the future, Lucy has just gone into labor, a week late. Someone important to both Lucy and Jack rush to their side, that person having her latest "movie star" date. And in present day, the entire Pearson family is descending on Los Angeles for Jack's first birthday, which will coincide with Kevin's one-year sobriety. While Kate, Toby and Jack welcome the family, they have a special Damon threesome-only secret task, out of which Kate and Toby discuss a not-yet-broached topic regarding their family. An announcement by Rebecca has the potential to overtake the day, while a series of events threaten Kevin making it to that one year.
—Huggo