▁season ▁premier ed ▁on ▁September ▁ 2 5 , ▁ 2 0 1 8 . ▁ ▁On ▁May ▁ 1 2 , ▁ 2 0 1 9 , ▁N BC ▁renew ed ▁the ▁series ▁for ▁three ▁additional ▁seasons . ▁The ▁fourth ▁season ▁premier ed ▁on ▁September ▁ 2 4 , ▁ 2 0 1 9 . ▁ ▁Series ▁over view ▁The ▁series ▁follows ▁the ▁lives ▁of ▁sib lings ▁Kevin , ▁Kate , ▁and ▁Rand all ▁( known ▁as ▁the ▁" Big ▁Three "), ▁and ▁their ▁parents ▁Jack ▁and ▁Reb e cca ▁Pear son . ▁It ▁takes ▁place ▁mainly ▁in ▁the ▁present ▁and ▁uses ▁flash back s ▁to ▁show ▁the ▁family ' s ▁past . ▁Kevin ▁and ▁Kate ▁are ▁the ▁two ▁surv iving ▁members ▁from ▁a ▁triple t ▁pre gn ancy , ▁born ▁six ▁weeks ▁prem ature ▁on ▁Jack ' s ▁ 3 6 th ▁birth day ▁in ▁ 1 9 8 0 ; ▁their ▁brother ▁is ▁still born . ▁Bel ieving ▁they ▁were ▁meant ▁to ▁have ▁three ▁children , ▁Jack ▁and ▁Reb e cca , ▁who ▁are ▁white , ▁decide ▁to ▁adopt ▁Rand all , ▁an ▁African ▁American ▁child ▁born ▁the ▁same ▁day ▁and ▁brought ▁to ▁the ▁same ▁hospital ▁after ▁his ▁bi ological ▁father ▁abandoned ▁him ▁at ▁a ▁fire ▁station . ▁Jack ▁dies ▁when ▁his ▁children ▁are ▁ 1 7 ▁and ▁Reb e cca ▁later ▁mar ries ▁Jack ' s ▁best ▁friend ▁Miguel . ▁ ▁Rand all ▁becomes ▁a ▁successful ▁fin ance ▁professional ▁and ▁mar ries ▁college ▁class mate ▁Beth ; ▁they ▁raise