Matriarch Rebecca Pearson begins to experience noticeable memory lapses. She is eventually diagnosed with mild cognitive impairment, heavily implied to be the early onset of Alzheimer's disease.
Tensions between the brothers reach an absolute breaking point over the course of the season, largely due to a fierce disagreement regarding Rebecca's medical care and clinical trials. This Is Us Season 4
The season premiere famously introduced three entirely new characters without immediate context. These included Cassidy, a military veteran struggling with PTSD; Malik, a teenage father in Philadelphia who falls for Deja; and a blind adult musician in the future who is revealed to be Kate and Toby's grown-up son, Jack Damon. The season premiere famously introduced three entirely new
Milo Ventimiglia (Jack), Mandy Moore (Rebecca), Sterling K. Brown (Randall), Chrissy Metz (Kate), and Justin Hartley (Kevin) all return as the core Pearson family. Brown (Randall), Chrissy Metz (Kate), and Justin Hartley