Join us for the Season 4, Episode 18 season finale of ‘This Is Us’ – “Strangers Part 2”. In the past timeline, Jack and Rebecca celebrate Kevin, Kate, and Randall’s 1st birthday. In the present timeline, the Philly Pearsons travel to California to celebrate Baby Jack’s 1st Birthday. Kevin and Randall face off regarding Rebecca’s treatment. Madison also has news for Kevin. In the future timelines, we met Jack and Lucy Damon’s daughter and there are other surprises as well in store for the Pearsons.