When Pete (Mark Wahlberg) and Ellie (Rose Byrne) decide to start a family, they explore the world of adoption. When they meet a trio of siblings, including a rebellious 15-year-old girl (Isabela Moner), they find themselves unexpectedly speeding from zero to three kids overnight. Now, Pete and Ellie must hilariously try to learn the ropes of instant parenthood in the hopes of becoming a family.